107. So, as we do not say that there are two Lords, when we so style both the Father and the Son, so, too, we do not say that there are three Lords, when we confess the Spirit to be Lord. For as it is profane to say that there are three Lords or three Gods, so, too, is it utter profanity to speak of two Lords or two Gods; for there is one God, one Lord, one Holy Spirit; and He Who is God is Lord, and He Who is Lord is God, for the Godhead is in the Lordship, and the Lordship is in the Godhead.
Complete source paragraph · On the Holy Spirit, Chapter XV., source paragraph 6 · Original source