Father Bernardin de Piconio’s Commentary on 2 Cor 13:9-13

9. For we rejoice that we are weak, and you are powerful. And this we pray for, your consummation.

10. Therefore I write this being absent, that I may not when present act with severity, according to the power which the Lord gave me, for edification, and not for destruction.
11. For the rest, brethren, rejoice, be perfect, exhort one another, be of one mind, be at peace, and the God of peace and love shall be with you.
12. Salute one another with a holy kiss. All the saints salute you.
13. The grace of our Lord Jesus Christ, and the charity of God, and the communication of the Holy Spirit, be with you all. Amen.

(verse 9) I shall be only too glad to find no occasion for the exercise of any such power, if you are strengthened in God’s grace, for what I most desire is your complete restoration to true faith and sanctity.  (verse 10) It is in the hope of this that I have used language of such apparent severity in this epistle, written from a distance, that I may be spared the necessity of acting with severity when I am among you. For God’s end and object in conferring miraculous power is attained by your edification, and he did not give them to destroy.  (verse 11) For the rest, and passing by the matters to which I have been referring, I desire you to rejoice in your Christian privileges and hopes; study daily to improve, and thus make progress towards perfection (St. Thomas); exhort, or as the Syriac reads, console one another in affliction or trouble, or otherwise, be consoled, for by God’s help all will in the end be well; try to be at concord in your views and sentiments; and live at peace with one another. God, who is the author of charity and peace, will be with you through His grace and charity. For God is charity, and who dwells in charity, dwells in God, and God in him. He is the God of peace, both as the author and proclaimer of peace between heaven and earth, pardon and reconciliation, to men of goodwill; and because his Gospel promotes peace among mankind, and his people live at peace with one another. And the God of charity, because he is charity himself, and love continually flows forth from the fountain of his sacred heart to ours; charity between God and man, and charity between Christians to one another.

(verse 12) Salute one another with a holy kiss, the symbol of a holy affection. Saint Chrysostom says: We are the temple of God, and of this temple the mouth is the vestibule, because by the visible channel of this vestibule Christ enters into us when we communicate. Therefore we kiss the threshold of the temple. St. Chrysostom. All the Saints, the Christians at Philippi in Macedonia, where this epistle was written.

The grace of salvation was sent us by the charity of God, and communicated to us by the Holy Spirit. All the elements of salvation are therefore included in this blessing. Ambrose.