9 This is the first proof: receive now a second plain one. The Lord said unto my Lord, sit Thou on My right hand. The Lord says this to the Lord, not to a servant, but to the Lord of all, and His own Son, to whom He put all things in subjection. But when He says that all things are put under Him, it is manifest that He is excepted, which did put all things under Him, and what follows; that God may be all in all. The Only-begotten Son is Lord of all, but the obedient Son of the Father, for He grasped not the Lordship, but received it by nature of the Father's own will. For neither did the Son grasp it, nor the Father grudge to impart it. He it is who says, All things are delivered unto Me of My Father; “delivered unto Me, not as though I had them not before; and I keep them well, not robbing Him who has given them.”
Source: Catechetical Lectures (New Advent)