Here we have,
I. The apostle's prayer to God on the behalf of the Corinthians, that they might do no evil, Co2 13:7. This is the most desirable thing we can ask of God, both for ourselves and for our friends, to be kept from sin, that we and they may do no evil; and it is most needful that we often pray to God for his grace to keep us, because without this we cannot keep ourselves. We are more concerned to pray that we may not do evil than that we may not suffer evil.
II. The reasons why the apostle put up this prayer to God on behalf of the Corinthians, which reasons have a special reference to their case, and the subject-matter about which he was writing to them. Observe, he tells them, 1. It was not so much for his own personal reputation as for the honour of religion: "Not that we should appear approved, but that you should do that which is honest, or decent, and for the credit of religion, though we should be reproached and vilified, and accounted as reprobates," Co2 13:7. Note, (1.) The great desire of faithful ministers of the gospel is that the gospel they preach may be honoured, however their persons may be vilified. (2.) The best way to adorn our holy religion is to do that which is honest, and of good report, to walk as becomes the gospel of Christ. 2. Another reason was this: that they might be free from all blame and censure when he should come to them. This is intimated in Co2 13:8, We can do nothing against the truth, but for the truth. If therefore they did not do evil, nor act contrary to their profession of the gospel, the apostle had no power nor authority to punish them. He had said before (Co2 10:8) and says here (Co2 13:10) that the power which the Lord had given him was to edification, not to destruction; so that, although the apostle had great powers committed to him for the credit and advancement of the gospel, yet he could not do anything to the disparagement of the truth, nor the discouragement of those who obeyed it. He could not, that is, he would not, he dared not, he had no commission to act against the truth; and it is remarkable how the apostle did rejoice in this blessed impotency: "We are glad," says he (Co2 13:9), "when we are weak and you are strong; that is, that we have no power to censure those who are strong in faith and fruitful in good works." Some understand this passage thus: "Though we are weak through persecutions and contempt, we bear it patiently, and also joyfully, while we see that you are strong, that you are prosperous in holiness, and persevering in well-doing." For, 3. He desired their perfection (Co2 13:9); that is, that they might be sincere, and aim at perfection (sincerity is our gospel-perfection), or else he wished there might be a thorough reformation among them. He not only desired that they might be kept from sin, but also that they might grow in grace, and increase in holiness, and that all that was amiss among them might be rectified and reformed. This was the great end of his writing this epistle, and that freedom he used with them by writing these things (those friendly admonitions and warnings), being absent, that so, being present, he should not use sharpness (Co2 13:10), that is, not proceed to the utmost extremity in the exercise of the power which the Lord had given him as an apostle, to revenge all disobedience, Co2 10:6.

For we are glad, when we are weak - It will give me indescribable pleasure that I should still appear to be poor, despicable, and destitute of this extraordinary power with which God has clothed me, so that you be strong in all the gifts and graces of the Holy Spirit.
And this also we wish, even your perfection - We cannot be satisfied that persons, with such eminent endowments, and who have once received the truth as it is in Jesus, should be deficient in any of the graces that constitute the mind of Christ; such as brotherly love, charity, harmony, unity, and order. I have given the above paraphrase to this verse, because of the last term καταρτισιν, which we render perfection. Καταρτισις, from κατα, intensive, andαρτιζω, to fit or adapt, signifies the reducing of a dislocated limb to its proper place; and hence, as Beza says on this passage: "The apostle's meaning is, that whereas the members of the Church were all, as it were, dislocated and out of joint, they should be joined together in love; and they should endeavor to make perfect what was amiss among them, either in faith or morals."
It is a metaphor, also, taken from a building; the several stones and timbers being all put in their proper places and situations, so that the whole building might be complete, and be a proper habitation for the owner. The same figure, though not in the same terms, the apostle uses, Eph 2:20-22.
The perfection or rejointing which the apostle wishes is that which refers to the state of the Church in its fellowship, unity, order, etc. And perfection in the soul is the same, in reference to it, as perfection in the Church is to its order and unity. The perfection or rejointing of the soul implies its purification, and placing every faculty, passion, and appetite in its proper place; so that the original order, harmony, unity, and purity of the soul may be restored; and the whole builded up to be a habitation of God through the Spirit, Eph 2:22.

Since ye seek a proof of Christ - The conversion of the Corinthians was to themselves a solid proof that Christ spoke by the apostle; and therefore he could, with great propriety, say that this power of Christ, far from being weak, was mighty among them.

For we are glad when we are weak,.... Appear to be so, look like persons disarmed of all power and authority; the apostles rejoiced when they had no occasion of exerting themselves, and of exercising that high office, and extraordinary commission they had received of Christ Jesus:

and ye are strong; stand fast in the doctrine of faith, and are lively and active in the exercise of the grace of faith; are strong in Christ, and in his grace, and in the power of his might, to withstand every temptation of Satan, every corruption of their own hearts, and to perform every duty aright.

And this also we wish, even your perfection; or restoration, or jointing in again; a metaphor taken from the setting of bones that are dislocated and out of joint; for the church at Corinth was like a disjointed body, and the apostle's wish was, that their animosities might cease, their divisions be healed, their disorders rectified, and each member be in its proper place, behaving as became the Gospel of Christ; see Co1 1:10.

are glad--Greek, "rejoice."

when we are weak--having no occasion for displaying our power; and so seeming "weak," as being compassed with "infirmities" (Co2 10:10; Co2 11:29-30).

ye . . . strong--"mighty" in faith and the fruits of the Spirit.

and--not in the oldest manuscripts.

we wish--Greek, "pray for."

your perfection--literally, "perfect restoration"; literally, that of a dislocated limb. Compare Co2 13:11, "Be perfect," the same Greek word; also in Co1 1:10, "perfectly joined together"; Eph 4:12, "the perfecting of the saints."