In the Old Testament (OT) it is clear that the inspired Bible writers intended holy spirit (ruah or ruach in Hebrew) to be understood as an invisible, powerful force from God. Even many trinitarian scholars will admit that.
For example, The Catholic Encyclopedia, p. 269, 1976, admits:
"In the OT the Holy Spirit means a divine power..."
And the New Bible Dictionary, Tyndale House Publishers, 1984, pp. 1136,1137, says:
"Spirit, Holy Spirit. OT, Heb. ruah 378 times ...; NT, Gk. pneuma 379 times." And "Divine power, where ruah is used to describe ... a supernatural force...." And "At its [the Old Testament's concept of ruah, God's spirit] heart is the experience of a mysterious, awesome power - the mighty invisible force of the wind, the mystery of its vitality, the otherly power that transforms - all ruah, all manifestations of divine energy." And "at this early stage [pre-Christian] of understanding, God's ruah was thought of simply as a supernatural power (under God's authority) exerting force in some direction."
The Encyclopedia Americana tells us:
"The doctrine of the Holy Spirit [as a person who is God] is a distinctly Christian [?] one.... the Spirit of Jehovah [in the OT] is the active divine principle in nature. .... But it is in the New Testament [NT] that we find the bases of the doctrine of the Spirit's personality." And "Yet the early Church did not forthwith attain to a complete doctrine; nor was it, in fact, until after the essential divinity of Jesus had received full ecclesiastical sanction [in 325 A.D. at the Council of Nicaea] that the personality of the Spirit was explicitly recognized, and the doctrine of the Trinity formulated." Also, "It is better to regard the Spirit as the agency which, proceeding from the Father and the Son, dwells in the church as the witness and power of the life therein." - Vol. 14, p. 326, 1957 ed.
And the Encyclopedia Britannica Micropaedia, 1985 ed., Vol. 6, p. 22 says:
"The Hebrew word ruah (usually translated `spirit') is often found in texts referring to the free and unhindered activity of God, .... There was, however, no explicit belief in a separate divine person in Biblical Judaism; in fact, the New Testament itself is not entirely clear in this regard....
"The definition that the Holy Spirit was a distinct divine Person equal in substance to the Father and the Son and not subordinate to them came at the Council of Constantinople in AD 381...."
Many historians and Bible scholars (most of them trinitarians) freely admit the above truth. For example: "On the whole, the New Testament, like the Old, speaks of the Spirit as a divine energy or power." - A Catholic Dictionary.
An Encyclopedia of Religion agrees:
"In the New Testament there is no direct suggestion of the Trinity. The Spirit is conceived as an impersonal power by which God effects his will through Christ." - p. 344, Virgilius Ferm, 1945 ed.
Even the trinitarian New Bible Dictionary tells us:
"It is important to realize that for the first Christians the Spirit was thought of in terms of divine power." - p. 1139, Tyndale House Publishers, 1984.
And the respected (and trinitarian) New International Dictionary of New Testament Theology confirms:
"As in earlier Jewish thought, pneuma [`spirit'] denotes that power which man experiences as relating him to the spiritual realm of reality which lies beyond ordinary observation and human control. Within this broad definition pneuma has a fairly wide range of meaning. But by far the most frequent use of pneuma in the NT (more than 250 times) is as a reference to the Spirit of God, the Holy Spirit, that power which is most immediately of God as to source and nature." - p. 693.
"The Spirit in the earliest Christian Communities and in Acts. `Holy Spirit' denotes supernatural power, altering, working through, directing the believer .... This is nowhere more clearly evident than in Acts where the Spirit is presented as an almost tangible force, visible if not in itself, certainly in its effects. This power of the Spirit manifests itself in three main areas in Luke's account of the early church [Acts]. (a) The Spirit as a transforming power in conversion. [p. 698] .... (b) The Spirit of prophecy. For the first Christians, the Spirit was most characteristically a divine power manifesting itself in inspired utterance. The same power that had inspired David and the prophets in the old age (Acts 1:16; 3:18; 4:25; 28:25) [p. 699] .... (c) The Spirit was evidently experienced as a numinous power pervading the early community ....
"The Spirit in the Pauline Letters. [p. 700] .... It is important to realize that for Paul too the Spirit is a divine power whose impact upon or entrance into a life is discernible by its effects." - pp. 693-701, Vol. 3, Zondervan, 1986.
"The emergence of Trinitarian speculations in early church theology led to great difficulties in the article about the Holy Spirit. For the being-as-person of the Holy Spirit, which is evident in the New Testament as divine power ..., could not be clearly grasped.... The Holy Spirit was viewed NOT AS A PERSONAL FIGURE BUT RATHER AS A POWER" - The New Encyclopedia Britannica.
For example, The Catholic Encyclopedia, p. 269, 1976, admits:
"In the OT the Holy Spirit means a divine power..."
And the New Bible Dictionary, Tyndale House Publishers, 1984, pp. 1136,1137, says:
"Spirit, Holy Spirit. OT, Heb. ruah 378 times ...; NT, Gk. pneuma 379 times." And "Divine power, where ruah is used to describe ... a supernatural force...." And "At its [the Old Testament's concept of ruah, God's spirit] heart is the experience of a mysterious, awesome power - the mighty invisible force of the wind, the mystery of its vitality, the otherly power that transforms - all ruah, all manifestations of divine energy." And "at this early stage [pre-Christian] of understanding, God's ruah was thought of simply as a supernatural power (under God's authority) exerting force in some direction."
The Encyclopedia Americana tells us:
"The doctrine of the Holy Spirit [as a person who is God] is a distinctly Christian [?] one.... the Spirit of Jehovah [in the OT] is the active divine principle in nature. .... But it is in the New Testament [NT] that we find the bases of the doctrine of the Spirit's personality." And "Yet the early Church did not forthwith attain to a complete doctrine; nor was it, in fact, until after the essential divinity of Jesus had received full ecclesiastical sanction [in 325 A.D. at the Council of Nicaea] that the personality of the Spirit was explicitly recognized, and the doctrine of the Trinity formulated." Also, "It is better to regard the Spirit as the agency which, proceeding from the Father and the Son, dwells in the church as the witness and power of the life therein." - Vol. 14, p. 326, 1957 ed.
And the Encyclopedia Britannica Micropaedia, 1985 ed., Vol. 6, p. 22 says:
"The Hebrew word ruah (usually translated `spirit') is often found in texts referring to the free and unhindered activity of God, .... There was, however, no explicit belief in a separate divine person in Biblical Judaism; in fact, the New Testament itself is not entirely clear in this regard....
"The definition that the Holy Spirit was a distinct divine Person equal in substance to the Father and the Son and not subordinate to them came at the Council of Constantinople in AD 381...."
Many historians and Bible scholars (most of them trinitarians) freely admit the above truth. For example: "On the whole, the New Testament, like the Old, speaks of the Spirit as a divine energy or power." - A Catholic Dictionary.
An Encyclopedia of Religion agrees:
"In the New Testament there is no direct suggestion of the Trinity. The Spirit is conceived as an impersonal power by which God effects his will through Christ." - p. 344, Virgilius Ferm, 1945 ed.
Even the trinitarian New Bible Dictionary tells us:
"It is important to realize that for the first Christians the Spirit was thought of in terms of divine power." - p. 1139, Tyndale House Publishers, 1984.
And the respected (and trinitarian) New International Dictionary of New Testament Theology confirms:
"As in earlier Jewish thought, pneuma [`spirit'] denotes that power which man experiences as relating him to the spiritual realm of reality which lies beyond ordinary observation and human control. Within this broad definition pneuma has a fairly wide range of meaning. But by far the most frequent use of pneuma in the NT (more than 250 times) is as a reference to the Spirit of God, the Holy Spirit, that power which is most immediately of God as to source and nature." - p. 693.
"The Spirit in the earliest Christian Communities and in Acts. `Holy Spirit' denotes supernatural power, altering, working through, directing the believer .... This is nowhere more clearly evident than in Acts where the Spirit is presented as an almost tangible force, visible if not in itself, certainly in its effects. This power of the Spirit manifests itself in three main areas in Luke's account of the early church [Acts]. (a) The Spirit as a transforming power in conversion. [p. 698] .... (b) The Spirit of prophecy. For the first Christians, the Spirit was most characteristically a divine power manifesting itself in inspired utterance. The same power that had inspired David and the prophets in the old age (Acts 1:16; 3:18; 4:25; 28:25) [p. 699] .... (c) The Spirit was evidently experienced as a numinous power pervading the early community ....
"The Spirit in the Pauline Letters. [p. 700] .... It is important to realize that for Paul too the Spirit is a divine power whose impact upon or entrance into a life is discernible by its effects." - pp. 693-701, Vol. 3, Zondervan, 1986.
"The emergence of Trinitarian speculations in early church theology led to great difficulties in the article about the Holy Spirit. For the being-as-person of the Holy Spirit, which is evident in the New Testament as divine power ..., could not be clearly grasped.... The Holy Spirit was viewed NOT AS A PERSONAL FIGURE BUT RATHER AS A POWER" - The New Encyclopedia Britannica.