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 can do nothing against the truth, but for the truth - As we are the apostles of God, we cannot bring to you any false doctrine; and, as we profess to be under the influence of God's Spirit, we cannot do any thing that is opposed to that truth, or which might be prejudicial to it. On the contrary, what we say and do is for that truth, to propagate and establish it. The Gospel of Jesus is truth; and my testimony concerning it is truth also. In my coming, and in my rod, you have nothing to fear, if you retain and abide in this truth.

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 can do nothing against the truth,.... The apostles had no power, nor could they, nor did they desire to exercise any against such who received the truth of the Gospel in the love of it; who continued in it, walked in it, and held it fast; who worshipped God in Spirit and in truth, and who walked uprightly, and as became the truth; for as the law is not made for such persons, but the reverse, so the authority the apostles had received from Christ was not to be exercised upon such:

but for the truth: for the sake of defending the truth against those that dropped, denied, and opposed it; and for the honour of it, by chastising, correcting, reproving, censuring, and punishing such, who either contradicted it, or caused it to be blasphemed and spoken evil of.

Our apostolic power is given us that we may use it not against, but for the furtherance of, the truth. Where you are free from fault, there is no scope for its exercise: and this I desire. Far be it from me to use it against the innocent, merely in order to increase my own power (Co2 13:10).