2Cor 5:20

“Seest thou how he has extolled the thing by introducing Christ thus in the form of a suppliant; yea rather not Christ only, but even the Father? For what he says is this: The Father sent the Son to beseech, and to be His Ambassador unto mankind. When then He was slain and gone, we succeeded to the embassy; and in His stead and the Father's we beseech you. So greatly doth He prize mankind that He gave up even the Son, and that knowing He would be slain, and made us Apostles for your sakes; so that he said with reason, "All things are for your sakes." "We are therefore ambassadors on behalf of Christ," that is, instead of Christ; for we have succeeded to His functions. But if this appears to thee a great thing, hear also what follows wherein he shows that they do this not in His stead only, but also in stead of the Father. For therefore he also added, "As though God were entreating by us." For not by the Son Himself only doth He beseech, but also by us who have succeeded to the office of the Son. Think not therefore, he says, that by us you are entreated; Christ Himself, the Father Himself of Christ, beseeches you by us. What can come up to this excess of goodness? He was outraged who had conferred innumerable benefits; having been outraged, He not only exacted not justice, but even gave His son that we might be reconciled. They that received Him were not reconciled, but even slew Him. Again, He sent other ambassadors to beseech, and though these are sent, it is Himself that entreats. And what doth He entreat? "Be ye reconciled unto God." And he said not, Reconcile God to yourselves; for it is not He that beareth enmity, but ye; for God never beareth enmity.”

“He says, "He [Christ] who knew no sin, he [God] made to be sin for us." The God to whom we are to be reconciled has thus made him the sacrifice for sin by which we may be reconciled. He himself is therefore sin as we ourselves are righteousness—not our own but God's, not in ourselves but in him. Just as he was sin—not his own but ours, rooted not in himself but in us—so he showed forth through the likeness of sinful flesh, in which he was crucified, that since sin was not in him he could then, so to say, die to sin by dying in the flesh, which was "the likeness of sin." And since he had never lived in the old manner of sinning, he might, in his resurrection, signify the new life which is ours, which is springing to life anew from the old death in which we had been dead to sin.”

“Let us consider the deeds of the Truth, that we may see where the actions of our depravity lie. For if we are members of the supreme Head, we ought to imitate Him to whom we are joined. For what does Paul, that outstanding preacher, say as an example for our instruction? "We are ambassadors for Christ, as though God were exhorting through us; we beseech you for Christ's sake, be reconciled to God." Behold, by sinning we have created discord between ourselves and God, and yet God first sent His ambassadors to us, so that we ourselves who sinned might come to peace with God when asked. Therefore let human pride be ashamed, let anyone be confounded who does not first make satisfaction to his neighbor, when after our fault, so that we might be reconciled to Him, God Himself who was offended beseeches us through intervening ambassadors.”

“"On behalf of Christ," that is, sent in place of Christ. For what He intended to do, we have now received, and as through Him the Father called us, so now through us He calls you to be reconciled with Him. He did not say: reconcile God to yourselves, but be reconciled with Him. For you are hostile toward Him, not He toward you, for God is also Father. He, as though He had sinned against them, sends to them so that they might forgive Him. O the riches of mercy and condescension!”

“Then when he says, So we are ambassadors for Christ, he indicates the use of the benefit. First, as to the second benefit conferred on the apostles; secondly, as to the first benefit conferred on all (v. 20b). He says therefore: since God has established the word of reconciliation, we ought to use it. This is why we are ambassadors for Christ: "For which I am an ambassador in chains; that I may declare it boldly, as I ought to speak" (Eph. 6:20). Our fitness for this ambassadorship is from God's power, which is in me. Hence he says, God making his appeal through us, because God, who speaks in us, makes us fit for this ambassadorship: "For it is not you who speak, but the Spirit of your Father speaking through you" (Matt. 10:20); "Since you desire proof that Christ is speaking in me" (2 Cor. 13:3). Then when he says, we beseech you, he describes the use of the first benefit. First, he exhorts to its use; secondly, he shows the source of his power to reconcile to God (v. 21). He says therefore: inasmuch as God has produced a reconciliation and we are ambassadors of God in this, we beseech you on behalf of Christ. He speaks gently, even though he could have commanded: "Convince, rebuke, and exhort, be unfailing in patience and in teaching" (2 Tim. 4:2); "Accordingly, though I am bold enough in Christ to command you to do what is required, yet for love's sake I prefer to appeal to you" (Phm. 1:8-9). We beseech you, I say, on behalf of Christ, i.e., for the love of Christ, to be reconciled to God. But this seems contrary to his statement that God has reconciled us to himself. Therefore, if he reconciled us, what need is there to be reconciled? For we are already reconciled. I answer that God reconciled us to himself as efficient cause, namely, on his part, but in order that it be meritorious for us, it is necessary that reconciliation be made on our part, namely, in baptism and in penance. And then we cease from sins.”