118. But if you are willing to learn that the Son of God knows all things, and has foreknowledge of all, see that those very things which you think to be unknown to the Son, the Holy Spirit received from the Son. He received them, however, through Unity of Substance, as the Son received from the Father. He, says He, shall glorify Me, for He shall receive of Mine and shall declare it unto you. All things whatsoever the Father has are Mine, therefore said I, He shall receive of Mine, and shall declare it unto you. [ John 16:14-15 ] What, then, is more clear than this Unity? What things the Father has pertain to the Son; what things the Son has the Holy Spirit also has received.
On the Holy Spirit, Book II