The Holy Spirit is God, being between the unbegotten and the begotten, and united to the Father through the Son μέσον τοῦ ἀγεννήτου καὶ τοῦ γεννητοῦ, καὶ δι᾽ Υἱοῦ τῷ Πατρὶ συναπτόμενον.. We speak of the Spirit of God, the Spirit of Christ, the mind of Christ, the Spirit of the Lord, the very Lord αὐτοκύριος., the Spirit of adoption, of truth, of liberty, of wisdom (for He is the creator of all these): filling all things with essence, maintaining all things, filling the universe with essence, while yet the universe is not the measure of His power.