Trinity

====Holy Spirit in later Christian theology====
As the [[Arian controversy]] was dissipating, the debate moved from the deity of Jesus Christ to the equality of the Holy Spirit with the Father and Son. On one hand, the [[Pneumatomachi]] sect declared that the Holy Spirit was an inferior person to the Father and Son. On the other hand, the [[Cappadocian Fathers]] argued that the Holy Spirit was equal to the Father and Son in nature or substance.

Although the main text used in defense of the deity of the Holy Spirit was Matthew 28:19, Cappadocian Fathers such as [[Basil the Great]] argued from other verses such as "But Peter said, 'Ananias, why has Satan filled your heart to lie to the Holy Spirit and to keep back for yourself part of the proceeds of the land? While it remained unsold, did it not remain your own? And after it was sold, was it not at your disposal? Why is it that you have contrived this deed in your heart? You have not lied to men but to God.{{' "}} (Acts 5:3–4).

Another passage the Cappadocian Fathers quoted from was "By the word of the Lord the heavens were made, and by the breath of his mouth all their host" (Psalm 33:6). According to their understanding, because "breath" and "spirit" in Hebrew are both "רוּחַ" ("ruach"), Psalm 33:6 is revealing the roles of the Son and Holy Spirit as co-creators. And since, according to them,{{sfn|Basil of Caesarea|1980|loc=Ch. 16}} because only the holy God can create holy beings such as the angels, the Son and Holy Spirit must be God.

Yet another argument from the Cappadocian Fathers to prove that the Holy Spirit is of the same nature as the Father and Son comes from "For who knows a person's thoughts except the spirit of that person, which is in him? So also no one comprehends the thoughts of God except the Spirit of God" (1 Corinthians 2:11). They reasoned that this passage proves that the Holy Spirit has the same relationship to God as the spirit within us has to us.{{sfn|Basil of Caesarea|1980|loc=Ch. 16}}

The Cappadocian Fathers also quoted, "Do you not know that you are God's temple and that God's Spirit dwells in you?" (1 Corinthians 3:16) and reasoned that it would be blasphemous for an inferior being to take up residence in a temple of God, thus proving that the Holy Spirit is equal with the Father and the Son.{{sfn|Basil of Caesarea|1980|loc=Ch. 19}}

They also combined "the servant does not know what his master is doing" (John 15:15) with 1 Corinthians 2:11 in an attempt to show that the Holy Spirit is not the slave of God, and therefore his equal.{{sfn|Basil of Caesarea|1980|loc=Ch. 21}}

The Pneumatomachi contradicted the Cappadocian Fathers by quoting, "Are they not all ministering spirits sent out to serve for the sake of those who are to inherit salvation?" (Hebrews 1:14) in effect arguing that the Holy Spirit is no different from other created angelic spirits.{{sfn|Arendzen|1911}} The Church Fathers disagreed, saying that the Holy Spirit is greater than the angels, since the Holy Spirit is the one who grants the foreknowledge for prophecy (1 Corinthians 12:8–10) so that the angels could announce events to come.{{sfn|Basil of Caesarea|1980|loc=Ch. 16}}