Heb 13:20

“Therefore having first asked their prayers, he then himself also prays for all good things on them. "Now the God of peace," he says (be ye not therefore at variance one with another), "that brought again from the earth the Shepherd of the sheep" (this is said concerning the resurrection) "the Great Shepherd" (another addition: here again he confirms to them even to the end, his discourse concerning the Resurrection) "through the blood of the everlasting covenant, our Lord Jesus Christ," "make you perfect in every good work, to do His will, working in you that which is well-pleasing in His sight." Again he bears high testimony to them. For that is made "perfect" which having a beginning is afterwards completed. And he prays for them which is the act of one who yearns for them. And while in the other Epistles, he prays in the prefaces, here he does it at the end. "Working in you," he says, "that which is well-pleasing in His sight through Jesus Christ, to whom be glory for ever and ever. Amen." Seest thou how he shows that virtue is born neither wholly from God, nor yet from ourselves alone? First by saying, "make you perfect in every good work"; Ye have virtue indeed, he means, but need to be made complete. What is "good work and word"? So as to have both life and doctrines right. "According to His will, working in you that which is well-pleasing in His sight." "In His sight," he says. For this is the highest virtue, to do that which is well-pleasing in the sight of God, as the Prophet also says, "And according to the cleanness of my hands in His eye-sight." (Ps. xviii. 24.)”

“First of all, having asked them for prayers and honored them by this, he then also prays for them himself. Since, he says, God is the God of peace, you should not be agitated against me, and moreover on the basis of mere hearsay alone. He instills in them the teaching about the resurrection, making use of the prophecy of Isaiah (Is. 10). And since there are also other shepherds—lesser ones—he said "great." For the prophets are many teachers, but Christ is the one instructor for all. That is, He raised Him from the dead after His death and after the shedding of His Blood, so that He gave us a covenant not subject, like the covenant of the law, to annulment, but an eternal one. For thus He raised Him from the dead with the Blood of the eternal covenant. For after the resurrection He granted us His Blood in a covenant. For if He had not risen, His Blood would not have served us as a covenant.”

“Then (v. 20) the Apostle prays for them. First, he prays; secondly, he excuses himself by asking something of them (v. 22). In regard to the first he describes the One Whom he seeks, saying the God of peace. For God's proper effect is to make peace, because 'he is not a God of dissension but of peace' (1 Cor. 14:33) and 'have peace: and the God of peace and love shall be with you' (2 Cor. 13:11). For peace is nothing more than unity of affections, which God alone can make one, because hearts are united by charity, which is from God alone. For God knows how to gather and unite, because God is love, which is the bond of perfection. Hence, 'he makes men of one manner to dwell in a house' (Ps. 67:7). For man made peace between himself and God through the ministry of Christ. Hence, he says, who brought again from the dead our Lord Jesus, the great shepherd of the sheep. But sometimes Christ is said to have been raised up by the Father's power: 'If the Spirit of him who raised Jesus Christ from the dead' (Rom. 8:11); and sometimes He is said to have raised Himself: 'I have slept and taken my rest: and I have risen up' (Ps. 3:6). But these statements are not contrary, because He rose by God's power, which is one in the Father and Son and Holy Spirit. Therefore, he brought him again from the dead, i.e., from the tomb, which is the place of the dead: 'As Christ rose from the dead by the glory of the Father, so we also shall walk in the newness of life' (Rom. 6:4). But Christ is called the great shepherd of the sheep, i.e., of the faithful and the humble: 'I am the good shepherd, and I know mine, and mine know me' (Jn. 10:14); for the sheep are they who obey God: 'And my sheep hear my voice' (Jn. 10:27). But he calls him the great shepherd, because all others are His vicars, for He feeds His own sheep, but the others feed Christ's sheep: 'Feed my sheep' (Jn. 21:17); 'When the prince of pastors shall appear, you shall receive a never fading crown of glory' (1 Pt 5:4). He brought Him out by the blood of the eternal covenant, i.e., in virtue of the blood of Christ by Whom is confirmed the New Covenant, in which eternal things are promised, but not in the Old. For Christ calls His blood the blood of the New Covenant; but the Apostle says, of the everlasting covenant. Therefore, both are mentioned in the words of the consecration of the Blood. But Christ by His passion merited the glory of His resurrection for Himself and for us; hence, he says, who brought again from the dead our Lord Jesus... by the blood of the eternal covenant: 'He humbled himself, being made obedient unto death' (Phil 2:8); 'By the blood of your testament you have sent forth your prisoners out of the pit, wherein is no water' (Zech 9:11).”

“"the God of peace." First, asking for their prayers and honoring them even in this way, Paul himself also prays for them. Since, he says, God is peace, you ought not to be stirred up against me from mere gossip and to have hostility. "who brought up from the dead the great Shepherd of the sheep." Which one? Our Lord, he says, Jesus. He affirms to them a certain word about the resurrection, taking the use from the prophecy of Isaiah (Isa. 40:11). And while there were also other shepherds, minor ones, he said the great one. For many are the prophets and teachers, but one is the instructor, Christ. "by the blood of the eternal covenant." That is to say, He raised him from the dead who had died, and having poured out his blood, that this might be for us an eternal covenant, that is, not to be cancelled, as the legal one, but everlasting. Thus: He raised him from the dead by the blood of an eternal covenant. For when he was raised, his blood was granted to us for an eternal covenant. For if he had not been raised, his blood would not have been for us a covenant.”