41 We have a sufficient and sacred guarantee for this belief in the authority of the Apostle. Through the Dispensation, and within time, the Lord Jesus Christ, the firstfruits of them that sleep, is to be subjected, that God may be all in all, and this subjection is not the debasement of His divinity, but the promotion of His assumed nature, for He Who is God and Man is now altogether God. But some may think that, when we say He was both glorified in the body while reigning in the body, and is hereafter to be subjected that God may be all in all, our belief finds no support for itself in the Gospels nor yet in the Epistles. We will, therefore, produce testimony of our faith, not only from the words of the Apostle, but also from our Lord's mouth. We will show that Christ said first with His own lips what He afterwards said by the mouth of Paul.
Source: On the Trinity (New Advent)