Will we need a Mediator even after the perfection brought about to God’s people after the Resurrection and the Last Judgment? In an interpretation of 1 Cor. 15.24 (“Then cometh the end, when he shall have delivered up the kingdom to God, even the Father; when he shall have put down all rule and all authority and power,” KJV) in Book 1 of On the Trinity, Augustine says “no,” and he does so via the dichotomy of “faith” and “sight.” That is, Augustine glosses the “delivering up of the kingdom” as bringing believers to contemplation of God by “sight” (which we do not enjoy now) without further need of intercession, which corresponds to “faith” (and which we do need now). It is, moreover, nothing by faith alone that brings a person to arrive at sight, the beholding of God “face to face.”
Our Lord Jesus Christ, therefore, will so deliver up the kingdom to God, even the Father, Himself not being thence excluded, nor the Holy Spirit, when He shall bring believers to the contemplation of God, wherein is the end of all good actions, and everlasting rest, and joy which never will be taken from us….For we shall then contemplate God, the Father and the Son and the Holy Spirit, when the Mediator between God and men, the man Christ Jesus, shall have delivered up the kingdom to God, even the Father, so as no longer to make intercession for us, as our Mediator and Priest, Son of God and Son of man; but that He Himself too, in so far as He is a Priest that has taken the form of a servant for us, shall be put under Him who has put all things under Him, and under whom He has put all things: so that, in so far as He is God, He with Him will have put us under Himself; in so far as He is a Priest, He with us will be put under Him.
When, therefore, Heshall have delivered up the kingdom to God, even the Father,— that is, when He shall have brought those who believe and live by faith, for whom now as Mediator He makes intercession, to that contemplation, for the obtaining of which we sigh and groan, and when labor and groaning shall have passed away—then, since the kingdom will have been delivered up to God, even the Father, He will no more make intercession for us. And this He signifies, when He says:These things have I spoken unto you in similitudes; but the time comes when I shall no more speak unto you in similitudes, but I shall declare to you plainly of the Father:that is, they will not then besimilitudes,when the sight shall beface to face.For this it is which He says,But I will declare to you plainly of the Father;as if He said I will plainly show you the Father. For He says, I willdeclareto you, because He is His word. For He goes on to say,At that day you shall ask in my name; and I say not unto you, that I will pray the Father for you: for the Father Himself loves you, because you have loved me, and have believed that I came out from God. I came forth from the Father, and have come into the world: again, I leave the world, and go to the Father.What is meant byI came forth from the Father,unless this, that I have not appeared in that form in which I am equal to the Father, but otherwise, that is, as less than the Father, in the creature which I have taken upon me? And what is meant byI have come into the world,unless this, that I have manifested to the eyes even of sinners who love this world, the form of a servant which I took, making myself of no reputation? And what is meant byAgain, I leave the world,unless this, that I take away from the sight of the lovers of this world that which they have seen? And what is meant byI go to the Father,unless this, that I teach those who are my faithful ones to understand me in that being in which I am equal to the Father? Those who believe this will be thought worthy of being brought by faith to sight, that is, to that very sight, in bringing them to which He is said todeliver up the kingdom to God, even the Father.For His faithful ones, whom He has redeemed with His blood, are called His kingdom, for whom He now intercedes; but then, making them to abide in Himself there, where He is equal to the Father, He will no longer pray the Father for them.For,He says,the Father Himself loves you.For indeed Heprays,in so far as He is less than the Father; but as He is equal with the Father, He with the Father grants. Wherefore He certainly does not exclude Himself from that which He says,The Father Himself loves you;but He means it to be understood after that manner which I have above spoken of, and sufficiently intimated,— namely, that for the most part each Person of the Trinity is so named, that the other Persons also may be understood. Accordingly,For the Father Himself loves you,is so said that by consequence both the Son and the Holy Spirit also may be understood: not that He does not now love us, who spared not His own Son, but delivered Him up for us all; but God loves us, such as we shall be, not such as we are, for such as they are whom He loves, such are they whom He keeps eternally; which shall then be, when He who now makes intercession for us shall havedelivered up the kingdom to God, even the Father,so as no longer to ask the Father, because the Father Himself loves us. But for what deserving, except of faith, by which we believe before we see that which is promised? For by this faith we shall arrive at sight; so that He may love us, being such, as He loves us in order that we may become; and not such, as He hates us because we are, and exhorts and enables us to wish not to be always. (On the Trinity 1.10.20-1)