More light less heat on exoplanets.

 

Study: Planets Capable of Sustaining Photosynthesis Are Extremely Rare

Casey Luskin

Headlines currently buzzing around the Internet are saying things like “Earth-like worlds capable of sustaining life may be less common than we thought” (CNET) or “There Is Only One Other Planet In Our Galaxy That Could Be Earth-Like, Say Scientists” (Forbes). While some might find it encouraging that there’s one other Earth-like planet in our galaxy, when you consider that there are 100 billion stars in the Milky Way galaxy alone, this certainly makes it sound like habitable planets are pretty special. 

The claims are based upon a new study in Monthly Notices of the Royal Astronomical Society, “Efficiency of the oxygenic photosynthesis on Earth-like planets in the habitable zone.” Photosynthesis, of course, is the basis of the biosphere for life on Earth, as the paper explains: 

Photosynthesis is the dominant process, as it allows us to produce about 99 per cent of the entire biomass of the Earth biosphere. OP is also essential for providing abundant O2 levels which appear to be necessary for the high-energy demands of multicellular life anywhere in the Universe.” A planet that can sustain photosynthesis thus has the ability to sustain a wide variety of other life forms. The study aims to estimate the ability of a planet to sustain oxygenic photosynthesis (OP) given three parameters: (1) the photon flux (i.e., the amount of light), (2) the “exergy,” which is a measure of the amount of work that can be done given the radiation input, and (3) something that can only be put in the words of the authors: “the exergetic efficiency of the radiation in the wavelength range useful for the oxygenic photosynthesis as a function of the host star effective temperature and planet-star separation.

Earth Has Highest Exergetic Efficiency

Let’s cut to the chase: The paper finds that among a database of planets both inside and outside our solar system, Earth is far and away the planet that is best-suited for life, with only one other planet with a radiation input that could possibly sustain oxygenic photosynthesis:

Earth is … the rocky planet with the largest PAR photon flux and with the highest exergetic efficiency. However, we also find that Kepler-442b receives a PAR photon flux slightly larger than the one necessary to sustain a large biosphere, similar to the Earth biosphere. So, it is likely that a Kepler-442b biosphere would not be light-limited.

Now of course the amount and type of radiation reaching a planet is crucial for its habitability. But there is a whole suite of additional features that are needed for advanced life to exist. This includes the presence of water (as well as the proper distance from the host star for the water to be in a liquid form), availability of necessary elements such as hydrogen, carbon, oxygen, and nitrogen, and the proper balance of other compounds such as carbon dioxide. To give a more complete list, planetary habitability requirements seem to include:

• Rocky planet with active plate tectonics to recycle elements needed for life
• Presence of sufficient water in the crust
• Large moon with right rotation period and distance
• Right planetary mass
• Presence of magnetic field
• Location within circumstellar habitable zone which allows liquid water to exist
• Low-eccentricity orbit to allow for stable climate
• Presence of large Jupiter-mass planetary neighbors in large circular orbits 
• Location outside spiral arm of galaxy and far enough from center of galaxy – the Galactic Habitable Zone
• Near co-rotation circle of galaxy, in circular orbit around galactic center
• Stable radiation output of host star
• Atmosphere which can allow visible light to penetrate to surface yet block out harmful radiation

We know that Earth meets all of these requirements, but does Kepler-442b? At this point we simply don’t know. 

A Planetary System Fit for Life

In his 2018 book Children of Light, Michael Denton elaborates on the last item in the list above — special properties of Earth’s atmosphere which allow radiation needed for “light-eating” organisms to reach the surface yet block out forms of radiation which are destructive to organic molecules. He explains that the electromagnetic radiation emitted by our sun is especially suited to the needs of life, and the atmosphere of Earth allows the precise wavelengths of radiation that are needed for photosynthesis:

[T]he electromagnetic radiation emitted by the Sun (and that of most other stars) is almost entirely light and heat (or infrared), which have precisely the characteristics needed for life, especially advanced life, to thrive on the Earth’s surface. Light is required for photosynthesis and heat is required to raise the Earth’s temperature to well above freezing and preserve liquid water on Earth.

It is only because of the precise absorption characteristics of Earth’s atmospheric gases that most of the light radiation emitted by the Sun reaches the Earth’s surface where it drives the chemical process of photosynthesis upon which we “light eaters” ultimately depend. And the same atmospheric gases which let the light through for photosynthesis absorb a portion of the infrared (IR) radiation, which warms the Earth and preserves water as a liquid on the Earth’s surface. Adding to the miracle, both the atmospheric gases and liquid water, the matrix of carbon-based life, not only let through the right light but strongly absorb all the dangerous types of radiant energy on either side of the visual and infrared regions of the electromagnetic spectrum, a vital property without which no advanced life forms would grace the surface of the Earth. 

CHILDREN OF LIGHT, PP. 15-16

Not only is Earth’s atmosphere precisely suited for the forms of EM radiation needed for life, but Denton explains that there’s a coincidence of chemistry wherein the very wavelengths of light that pass through our atmosphere can activate organic molecules yet not destroy them: 

Within this Goldilocks region, the light is not so energetic as to cause chemical disruption of organic matter, but it is energetic enough to gently activate organic molecules for chemical reaction. In other words “just right.” No other EM radiation will do! As Wald points out, it is not that life adapted to the right light but that the right light is the only light that provides the correct energy levels for photochemistry: 

“There cannot be a planet on which photosynthesis or vision occurs in the far infrared or far ultraviolet, because these radiations are not appropriate to perform these functions. It is not the range of available radiation that sets the photobiological domain, but rather the availability of the proper range of wavelengths that decides whether living organisms can develop and light can act upon them in useful ways.”

CHILDREN OF LIGHT, PP. 25, EMPHASIS IN ORIGINAL

Both Earth and our sun form a finely balanced system that is finely tuned to allow photosynthesis to occur. We don’t know that this overall system exists on Kepler-442b. 

Underestimating the Complexity of Photosynthesis

Have you ever heard of those “ghost malls” in China? They were fully built and ready for business — including one that was arguably the largest mall in the world. Everything was just right for business, but they were missing one thing: vendors and customers. In a similar way, having the right kind of sun and planetary atmosphere aren’t the only requirements for photosynthesis. You could have a planet that is perfectly habitable for life yet if life never arises it will be empty. Organisms capable of photosynthesis itself must somehow arise. But how? Reflecting a common form of evolutionary thinking, the new paper discussed above seems to suggest that once the right conditions are present, photosynthesis can evolve quite easily. In one passage it describes the familiar basic chemical equation for photosynthesis and then lauds its “overall simplicity”:

6CO2 + 6H2O + light → C6H12O6 + 6O2 (1)

We conjecture that the chemical reaction (1) should be quite common in the cosmos because of the generally large amounts of radiation received by exoplanets from their host stars, the availability of the input ingredients, and its overall simplicity supported by the fact that OP evolved very early on Earth.

As the paper suggests, photosynthesis is the conversion of light into chemical energy. This is a process that happens in the leaves of plants and requires five highly specialized protein complexes (photosystems I & II, cytochrome bf complex, NADPH reductase, and ATP synthase) for the light reactions and 11 enzymes for the dark reactions. Briefly, in the light reactions, a photon is captured by an antenna pigment, and the energy of excited electrons is then transferred to chlorophyll molecules. A high-energy electron from chlorophyll is passed through an electron transport chain which causes the pumping of protons across a membrane. Those protons are used to power the ATP synthase molecular machine which generates ATP, the energy molecule of the cell.  And of course ATP synthase alone is a multicomponent irreducibly complex molecular machine:

The dark reactions of photosynthesis are where you fix carbon by taking in CO2 and make a carbohydrate which the organism can further use. This whole process is called the Calvin cycle and over the series of 11 enzyme-controlled steps you have a tightly controlled process that generates either energy molecules or structural molecules or both depending on what the cell needs.

Michael Denton provides his own nice sketch of the complexity of photosynthesis:

The primary event on which the whole process of photosynthesis depends is the capture or absorption of photons of light by the photosynthetic pigments (chiefly the green pigment chlorophyll) in the thylakoid membranes (which surround the so-called thylakoid discs in the chloroplast). When the chlorophyll molecules situated in these membranes capture photons, the energy imparted activates electrons in the chlorophyll, raising them to higher energy levels. (Each photon absorbed raises one electron to a higher energy level.) 

This allows the electrons to escape from the chlorophyll, leaving the chlorophyll molecules positively charged or oxidized. (The loss of electrons is oxidation.) The positively charged chlorophylls draw electrons from water molecules (H2O) in the oxygen-evolving complex (OEC), oxidizing them and releasing at the same time free oxygen (0) molecules, as well as protons (H+) and electrons (e-).

Water [H20] → Oxygen [02] + protons [H+] + electrons [e-]

The energetic electrons escaping from the chlorophyll find their way to electron transport chains, where they flow “down” in discrete steps, releasing energy at each step, which is used to do work, pumping protons (H+) across a membrane (the thylakoid membrane) into the thylakoid lumen (a membrane-enclosed compartment in the chloroplast). These then flow back through the same membrane, providing energy to drive the synthesis of ATP (the cell’s chemical energy currency) by the enzyme ATP synthase. 

[…]

Overall, photosynthesis can be seen to occur in two stages. In the first stage, light-dependent reactions capture the energy of light and use it to make the energy-storage molecule A TP and the reducing agent NADPH. These light-dependent reactions occur in the thylakoid membranes. During the second stage (the Calvin cycle), the light-independent reactions use these products to reduce carbon dioxide. 

CHILDREN OF LIGHT, PP. 75-77

Of course each of these steps requires finely tuned enzymes, cofactors, and other biomolecules which facilitate the requisite chemical reactions. It may even represent an irreducibly complex system. 

So how did the paper determine that photosynthesis has an “overall simplicity,” despite the complexity just described? Only due, again, to evolutionary thinking: photosynthesis appears early in life’s history, and because they presume that unguided evolution is the only mechanism by which complex biological systems can arise, they therefore conclude that photosynthesis must be simple and easy to evolve. But as we have seen it’s not simple at all. Having the right conditions for photosynthesis to take place doesn’t in any way guarantee that photosynthesis will evolve. Compared to evolving the complexity of photosynthesis, obtaining the rare special conditions where a planet receives the EM radiation needed for photosynthesis seems like a much simpler task — even though it’s apparently very rare in the universe! 

The Watchtower society's commentary on prayer.

 

PRAYER

Worshipful address to the true God, or to false gods. Mere speech to God is not necessarily prayer, as is seen in the judgment in Eden and in the case of Cain. (Ge 3:8-13; 4:9-14) Prayer involves devotion, trust, respect, and a sense of dependence on the one to whom the prayer is directed. The various Hebrew and Greek words relating to prayer convey such ideas as to ask, make request, petition, entreat, supplicate, plead, beseech, beg, implore favor, seek, inquire of, as well as to praise, thank, and bless.

Petitions and supplications, of course, can be made to men, and the original-language words are sometimes so used (Ge 44:18; 50:17; Ac 25:11), but “prayer,” used in a religious sense, does not apply to such cases. One might “beseech” or “implore” another person to do something, but in so doing he would not view this individual as his God. He would not, for example, silently petition such one, nor do so when the individual was not visibly present, as one does in prayer to God.

The “Hearer of Prayer.” The entire Scriptural record testifies that Jehovah is the One to whom prayer should be directed (Ps 5:1, 2; Mt 6:9), that he is the “Hearer of prayer” (Ps 65:2; 66:19) and has power to act in behalf of the petitioners. (Mr 11:24; Eph 3:20) To pray to false gods and their idol images is exposed as stupidity, for the idols do not have the ability either to hear or to act, and the gods they represent are unworthy of comparison with the true God. (Jg 10:11-16; Ps 115:4, 6; Isa 45:20; 46:1, 2, 6, 7) The contest concerning godship between Baal and Jehovah, held on Mount Carmel, demonstrated the foolishness of prayer to false deities.​—1Ki 18:21-39; compare Jg 6:28-32.

Though some claim that prayer may properly be addressed to others, such as to God’s Son, the evidence is emphatically to the contrary. True, there are rare instances in which words are addressed to Jesus Christ in heaven. Stephen, when about to die, appealed to Jesus, saying, “Lord Jesus, receive my spirit.” (Ac 7:59) However, the context reveals a circumstance giving basis for this exceptional expression. Stephen at that very time had a vision of “Jesus standing at God’s right hand,” and evidently reacting as if he were in Jesus’ personal presence, he felt free to speak this plea to the one whom he recognized as the head of the Christian congregation. (Ac 7:55, 56; Col 1:18) Similarly, the apostle John, at the conclusion of the Revelation, says, “Amen! Come, Lord Jesus.” (Re 22:20) But again the context shows that, in a vision (Re 1:10; 4:1, 2), John had been hearing Jesus speak of his future coming and thus John responded with the above expression of his desire for that coming. (Re 22:16, 20) In both cases, that of Stephen and that of John, the situation differs little from that of the conversation John had with a heavenly person in this Revelation vision. (Re 7:13, 14; compare Ac 22:6-22.) There is nothing to indicate that Christian disciples so expressed themselves under other circumstances to Jesus after his ascension to heaven. Thus, the apostle Paul writes: “In everything by prayer and supplication along with thanksgiving let your petitions be made known to God.”​—Php 4:6.

The article APPROACH TO GOD considers the position of Christ Jesus as the one through whom prayer is directed. Through Jesus’ blood, offered to God in sacrifice, “we have boldness for the way of entry into the holy place,” that is, boldness to approach God’s presence in prayer, approaching “with true hearts in the full assurance of faith.” (Heb 10:19-22) Jesus Christ is therefore the one and only “way” of reconciliation with God and approach to God in prayer.​—Joh 14:6; 15:16; 16:23, 24; 1Co 1:2; Eph 2:18; see JESUS CHRIST (His Vital Place in God’s Purpose).

Those Whom God Hears. People “of all flesh” may come to the “Hearer of prayer,” Jehovah God. (Ps 65:2; Ac 15:17) Even during the period that Israel was God’s “private property,” his covenant people, foreigners could approach Jehovah in prayer by recognizing Israel as God’s appointed instrument and the temple at Jerusalem as his chosen place for sacrifice. (De 9:29; 2Ch 6:32, 33; compare Isa 19:22.) Later, by Christ’s death, the distinction between Jew and Gentile was forever removed. (Eph 2:11-16) At the home of the Italian Cornelius, Peter recognized that “God is not partial, but in every nation the man that fears him and works righteousness is acceptable to him.” (Ac 10:34, 35) The determining factor, then, is the heart of the individual and what his heart is moving him to do. (Ps 119:145; La 3:41) Those who observe God’s commandments and do “the things that are pleasing in his eyes” have the assurance that his “ears” are also open to them.​—1Jo 3:22; Ps 10:17; Pr 15:8; 1Pe 3:12.

Conversely, those who disregard God’s Word and law, shedding blood and practicing other wickedness, do not receive a favorable hearing from God; their prayers are “detestable” to him. (Pr 15:29; 28:9; Isa 1:15; Mic 3:4) The very prayer of such ones can “become a sin.” (Ps 109:3-7) King Saul, by his presumptuous, rebellious course, lost God’s favor, and “although Saul would inquire of Jehovah, Jehovah never answered him, either by dreams or by the Urim or by the prophets.” (1Sa 28:6) Jesus said that hypocritical persons who sought to draw attention to their piety by praying received their “reward in full”​—from men, but not from God. (Mt 6:5) The pious-appearing Pharisees made long prayers, boasted of their superior morality, yet were condemned by God for their hypocritical course. (Mr 12:40; Lu 18:10-14) Though they drew near with their mouths, their hearts were far from God and his Word of truth.​—Mt 15:3-9; compare Isa 58:1-9.

The individual must have faith in God and in his being “the rewarder of those earnestly seeking him” (Heb 11:6), approaching in “the full assurance of faith.” (Heb 10:22, 38, 39) Recognition of one’s own sinful state is essential, and when serious sins have been committed, the individual must ‘soften the face of Jehovah’ (1Sa 13:12; Da 9:13) by first softening his own heart in sincere repentance, humility, and contrition. (2Ch 34:26-28; Ps 51:16, 17; 119:58) Then God may let himself be entreated and may grant forgiveness and a favorable hearing (2Ki 13:4; 2Ch 7:13, 14; 33:10-13; Jas 4:8-10); no longer will one feel that God has ‘blocked approach to himself with a cloud mass, that prayer may not pass through.’ (La 3:40-44) Though a person may not be cut off completely from receiving audience with God, his prayers can be “hindered” if he fails to follow God’s counsel. (1Pe 3:7) Those seeking forgiveness must be forgiving toward others.​—Mt 6:14, 15; Mr 11:25; Lu 11:4.

What are proper matters about which to pray?

Basically prayers involve confession (2Ch 30:22), petitions or requests (Heb 5:7), expressions of praise and thanksgiving (Ps 34:1; 92:1), and vows (1Sa 1:11; Ec 5:2-6). The prayer given by Jesus to his disciples was evidently a model, or a basic pattern, because later prayers by Jesus himself, as well as by his disciples, did not rigidly adhere to the specific words of his model prayer. (Mt 6:9-13) In its initial words, this prayer concentrates on the matter of primary concern, the sanctification of Jehovah’s name, which name began to be profaned by the rebellion in Eden, as well as on the realization of the divine will by means of the promised Kingdom, which government is headed by the prophesied Seed, the Messiah. (Ge 3:15; see JEHOVAH [Sovereignty to Be Vindicated and Name to Be Sanctified].) Such prayer requires that the one praying be definitely on God’s side in the issue involving Jehovah’s sovereignty.

Jesus’ parable at Luke 19:11-27 shows what the ‘coming of the Kingdom’ means​—its coming to execute judgment, to destroy all opposers, and to bring relief and reward to those hoping in it. (Compare Re 16:14-16; 19:11-21.) The following expression, “let your will take place, as in heaven, also upon earth,” thus refers primarily, not to the doing of God’s will by humans, but, rather, to God’s own acting in fulfillment of his will toward the earth and its inhabitants, manifesting his power to realize his declared purpose. The person praying, of course, also expresses thereby his own preference for, and submission to, that will. (Mt 6:10; compare Mt 26:39.) The request for daily bread, forgiveness, protection against temptation, and deliverance from the wicked one all relate to the petitioner’s desire to continue living in God’s favor. He expresses this desire for all others of like faith, not for himself alone.​—Compare Col 4:12.

These matters in this model prayer are of fundamental importance to all men of faith and express needs they all have in common. The Scriptural account shows that there are, on the other hand, many other matters that may affect individuals to a greater or lesser degree or that result from particular circumstances or occasions and that are also proper subjects for prayer. Though not specifically mentioned in Jesus’ model prayer, they are, nevertheless, related to the matters there presented. Personal prayers, then, may embrace virtually every facet of life.​—Joh 16:23, 24; Php 4:6; 1Pe 5:7.

Thus, all rightly seek increased knowledge, understanding, and wisdom (Ps 119:33, 34; Jas 1:5); yet some may need such in special ways. They may call on God for guidance in matters of judicial decisions, as did Moses (Ex 18:19, 26; compare Nu 9:6-9; 27:1-11; De 17:8-13), or in the appointment of persons to special responsibility among God’s people. (Nu 27:15-18; Lu 6:12, 13; Ac 1:24, 25; 6:5, 6) They may seek strength and wisdom to carry out certain assignments or to face up to particular trials or dangers. (Ge 32:9-12; Lu 3:21; Mt 26:36-44) Their reasons for blessing God and thanking him may vary according to their own personal experiences.​—1Co 7:7; 12:6, 7; 1Th 5:18.

At 1 Timothy 2:1, 2, the apostle speaks of prayers being made “concerning all sorts of men, concerning kings and all those who are in high station.” On his final night with his disciples, Jesus, in prayer, said that he did not make request concerning the world, but concerning those whom God had given him, and that these were not of the world but were hated by the world. (Joh 17:9, 14) It therefore appears that Christian prayers regarding officials of the world are not without limitation. The apostle’s further words indicate that such prayers are ultimately in favor of God’s people, “in order that we may go on leading a calm and quiet life with full godly devotion and seriousness.” (1Ti 2:2) Earlier examples illustrate this: Nehemiah prayed that God would ‘give him pity’ before King Artaxerxes (Ne 1:11; compare Ge 43:14), and Jehovah instructed the Israelites to “seek the peace of the city [Babylon]” in which they would be exiled, praying on its behalf, since “in its peace there will prove to be peace for you yourselves.” (Jer 29:7) Similarly, Christians prayed concerning the threats of the rulers in their day (Ac 4:23-30), and undoubtedly their prayers in behalf of imprisoned Peter also involved the officials with authority to release him. (Ac 12:5) In harmony with Christ’s counsel, they prayed for those persecuting them.​—Mt 5:44; compare Ac 26:28, 29; Ro 10:1-3.

Giving thanks for God’s provisions, such as food, was done from early times. (De 8:10-18; note also Mt 14:19; Ac 27:35; 1Co 10:30, 31.) Appreciation for God’s goodness, however, is to be shown in “everything,” not only for material blessings.​—1Th 5:17, 18; Eph 5:19, 20.

In the final analysis, it is knowledge of God’s will that governs the contents of a person’s prayers, for the supplicant must realize that, if his request is to be granted, it must please God. Knowing that the wicked and those disregarding God’s Word have no favor with Him, the supplicant obviously cannot request that which runs counter to righteousness and to God’s revealed will, including the teachings of God’s Son and his inspired disciples. (Joh 15:7, 16) Thus, statements regarding the asking of “anything” (Joh 16:23) are not to be taken out of context. “Anything” clearly does not embrace things the individual knows, or has reason to believe, are not pleasing to God. John states: “This is the confidence that we have toward him, that, no matter what it is that we ask according to his will, he hears us.” (1Jo 5:14; compare Jas 4:15.) Jesus told his disciples: “If two of you on earth agree concerning anything of importance that they should request, it will take place for them due to my Father in heaven.” (Mt 18:19) While material things, such as food, are proper subjects of prayer, materialistic desires and ambitions are not, as such texts as Matthew 6:19-34 and 1 John 2:15-17 show. Nor can one rightly pray for those whom God condemns.​—Jer 7:16; 11:14.

Romans 8:26, 27 shows that the Christian, under certain circumstances, will not know just what to pray for; but his unuttered ‘groanings’ are nonetheless understood by God. The apostle shows that this is by means of God’s spirit, or active force. It should be remembered that it was by his spirit that God inspired the Scriptures. (2Ti 3:16, 17; 2Pe 1:21) These included events and circumstances similar to those that would come upon his servants in later times and showed the way in which God would guide his servants and bring them the help they needed. (Ro 15:4; 1Pe 1:6-12) It may not be until after the needed help has been received that the Christian realizes that what he might have prayed for (but did not know how to) was already set forth in God’s spirit-inspired Word.​—Compare 1Co 2:9, 10.

The Answering of Prayers. Although God anciently carried on a measure of two-way communication with certain individuals, this was not common, for the most part being restricted to special representatives, such as Abraham and Moses. (Ge 15:1-5; Ex 3:11-15; compare Ex 20:19.) Even then, with the exception of when he spoke to or about his Son while on earth, God’s words were evidently transmitted through angels. (Compare Ex 3:2, 4; Ga 3:19.) Messages delivered personally by materialized angels were likewise uncommon, as is evidenced by the disturbed effect they generally produced on the receivers. (Jg 6:22; Lu 1:11, 12, 26-30) The answering of prayers in the majority of cases, therefore, was through prophets or by the granting of, or the refusal to grant, the request. Jehovah’s answers to prayers often had a clearly recognizable effect, as when he delivered his servants from their enemies (2Ch 20:1-12, 21-24) or when he provided for their physical needs in times of dire scarcity. (Ex 15:22-25) But undoubtedly the most frequent answer was not so easily discernible, since it related to giving moral strength and enlightenment, enabling the person to hold to a righteous course and carry out divinely assigned work. (2Ti 4:17) Particularly for the Christian the answer to prayers involved matters mainly spiritual, not as spectacular as some powerful acts of God in earlier times, but equally vital.​—Mt 9:36-38; Col 1:9; Heb 13:18; Jas 5:13.

Acceptable prayer must be made to the right person, Jehovah God; on right matters, those in harmony with God’s declared purposes; in the right manner, through God’s appointed way, Christ Jesus; and with a right motive and a clean heart. (Compare Jas 4:3-6.) Along with all of this, there is need for persistence. Jesus said to ‘keep on asking, seeking, and knocking,’ not giving up. (Lu 11:5-10; 18:1-7) He raised the question as to whether, at his future ‘arrival,’ he would find faith in the power of prayer on earth. (Lu 18:8) The seeming delay on God’s part in answering some prayers is not due to any inability nor to a lack of willingness, as the Scriptures make clear. (Mt 7:9-11; Jas 1:5, 17) In some cases the answer must await God’s ‘timetable.’ (Lu 18:7; 1Pe 5:6; 2Pe 3:9; Re 6:9-11) Primarily, however, it is evident that God allows his petitioners to demonstrate the depth of their concern, the intensity of their desire, the genuineness of their motive. (Ps 55:17; 88:1, 13; Ro 1:9-11) At times they must be like Jacob in his wrestling a long time in order to obtain a blessing.​—Ge 32:24-26.

Similarly, while Jehovah God cannot be pressured by numbers into acting, he evidently takes note of the extent of concern shown among his servants as a body, taking action when they collectively show deep concern and united interest. (Compare Ex 2:23-25.) Where apathy or a measure of it exists, God may withhold action. In the reconstruction of Jerusalem’s temple, a project for some time not well supported (Ezr 4:4-7, 23, 24; Hag 1:2-12), there were interruptions and delay, whereas later, in Nehemiah’s reconstruction of the city walls, accomplished with prayer and good support, the work was done in just 52 days. (Ne 2:17-20; 4:4-23; 6:15) Writing the Corinthian congregation, Paul speaks of God’s deliverance of him from danger of death, and he states: “You also can help along by your supplication for us, in order that thanks may be given by many in our behalf for what is kindly given to us due to many prayerful faces.” (2Co 1:8-11; compare Php 1:12-20.) The power of intercessory prayer is regularly stressed, whether by an individual or a collective group. It was in regard to ‘praying for one another’ that James said: “A righteous man’s supplication, when it is at work, has much force.”​—Jas 5:14-20; compare Ge 20:7, 17; 2Th 3:1, 2; Heb 13:18, 19.

Also notable is the frequent ‘pleading’ of one’s case before Jehovah, the Sovereign Ruler. The petitioner presents reasons why he believes the request to be right, evidence of his having a right and unselfish motive, and reasoning to show that there are other factors outweighing his own interests or considerations. These might be that the honor of God’s own name or the good of his people is involved, or they may include the effect on others as a result of God’s action or refusal to act. Appeals may be made to God’s justice, his loving-kindness, his being a God of mercy. (Compare Ge 18:22-33; 19:18-20; Ex 32:11-14; 2Ki 20:1-5; Ezr 8:21-23.) Christ Jesus also ‘pleads’ for his faithful followers.​—Ro 8:33, 34.

The entire book of Psalms consists of prayers and songs of praise to God, its contents illustrating what prayer should be. Among many notable prayers are those by Jacob (Ge 32:9-12), Moses (De 9:25-29), Job (Job 1:21), Hannah (1Sa 2:1-10), David (2Sa 7:18-29; 1Ch 29:10-19), Solomon (1Ki 3:6-9; 8:22-61), Asa (2Ch 14:11), Jehoshaphat (2Ch 20:5-12), Elijah (1Ki 18:36, 37), Jonah (Jon 2:1-9), Hezekiah (2Ki 19:15-19), Jeremiah (Jer 20:7-12; the book of Lamentations), Daniel (Da 9:3-21), Ezra (Ezr 9:6-15), Nehemiah (Ne 1:4-11), certain Levites (Ne 9:5-38), Habakkuk (Hab 3:1-19), Jesus (Joh 17:1-26; Mr 14:36), and Jesus’ disciples (Ac 4:24-30).​—See ATTITUDES AND GESTURES; INCENSE (Significance).