In these verses observe,

I.The apostle threatens to be severe against obstinate sinners when he should come to Corinth, having now sent to them a first and second epistle, with proper admonitions and exhortations, in order to reform what was amiss among them. Concerning this we may notice, 1. The caution with which he proceeded in his censures: he was not hasty in using severity, but gave a first and second admonition. So some understand his words (Co2 13:1): This is the third time I am coming to you, referring to his first and second epistles, by which he admonished them, as if he were present with them, though in person he was absent, Co2 13:2. According to this interpretation, these two epistles are the witnesses he means in the first verse, referring rather to the direction of our Saviour (Mat 17:16) concerning the manner how Christians should deal with offenders before they proceed to extremity than to the law of Moses (Deu 17:6; Deu 19:15) for the behaviour of judges in criminal matters. We should go, or send, to our brother, once and again, to tell him of his fault. Thus the apostle had told these Corinthians before, in his former epistle, and now he tells them, or writes to those who heretofore had sinned, and to all others, giving warning unto all before he came in person the third time, to exercise severity against scandalous offenders. Others think that the apostle had designed and prepared for his journey to Corinth twice already, but was providentially hindered, and now informs them of his intentions a third time to come to them. However this be, it is observable that he kept an account how often he endeavoured, and what pains he took with these Corinthians for their good: and we may be sure that an account is kept in heaven, and we must be reckoned with another day for the helps we have had for our souls, and how we have improved them. 2. The threatening itself: That if (or when) he came again (in person) he would not spare obstinate sinners, and such as were impenitent, in their scandalous enormities. He had told them before, he feared God would humble him among them, because he should find some who had sinned and had not repented; and now he declares he would not spare such, but would inflict church-censures upon them, which are thought to have been accompanied in those early times with visible and extraordinary tokens of divine displeasure. Note, Though it is God's gracious method to bear long with sinners, yet he will not bear always; at length he will come, and will not spare those who remain obstinate and impenitent, notwithstanding all his methods to reclaim and reform them.

II.The apostle assigns a reason why he would be thus severe, namely, for a proof of Christ's speaking in him, which they sought after, Co2 13:3. The evidence of his apostleship was necessary for the credit, confirmation, and success, of the gospel he preached; and therefore such as denied this were justly and severely to be censured. It was the design of the false teachers to make the Corinthians call this matter into question, of which yet they had not weak, but strong and mighty proofs (Co2 13:3), notwithstanding the mean figure he made in the world and the contempt which by some was cast upon him. Even as Christ himself was crucified through weakness, or appeared in his crucifixion as a weak and contemptible person, but liveth by the power of God, or in his resurrection and life manifests his divine power (Co2 13:4), so the apostles, how mean and contemptible soever they appeared to the world, did yet, as instruments, manifest the power of God, and particularly the power of his grace, in converting the world to Christianity. And therefore, as a proof to those who among the Corinthians sought a proof of Christ's speaking in the apostle, he puts them upon proving their Christianity (Co2 13:5): Examine yourselves, etc. Hereby he intimates that, if they could prove their own Christianity, this would be a proof of his apostleship; for if they were in the faith, if Jesus Christ was in them, this was a proof that Christ spoke in him, because it was by his ministry that they did believe. He had been not only an instructor, but a father to them. He had begotten them again by the gospel of Christ. Now it could not be imagined that a divine power should go along with his ministrations if he had not his commission from on high. If therefore they could prove themselves not to be reprobates, not to be rejected of Christ, he trusted they would know that he was not a reprobate (Co2 13:6), not disowned by Christ. What the apostle here says of the duty of the Corinthians to examine themselves, etc., with the particular view already mentioned, is applicable to the great duty of all who call themselves Christians, to examine themselves concerning their spiritual state. We should examine whether we be in the faith, because it is a matter in which we may be easily deceived, and wherein a deceit is highly dangerous: we are therefore concerned to prove our own selves, to put the question to our own souls, whether Christ be in us, or not; and Christ is in us, except we be reprobates: so that either we are true Christians or we are great cheats; and what a reproachful thing is it for a man not to know himself, not to know his own mind!

I told you before, etc. - As Calmet maintains that Paul had already been twice at Corinth, it is well to hear his reasons: "St. Paul came to Corinth the latter end of the year of our Lord 52, and remained there eighteen months, Act 18:1, etc. He came there a second time in the year 55, but stayed only a short time, as he had to return speedily to Ephesus, Co1 16:7; hence it is that St. Luke makes no mention of this second journey in the Acts. Finally he determined to visit them a third time; as in effect he did about the year 57. Of his second voyage to Corinth, which is not mentioned in the Acts, he speaks expressly in this verse." I do not see sufficient evidence to induce me to subscribe to this opinion of Calmet. I believe the apostle had been but once before at Corinth; and this matter is set in a clear point of view by Dr. Paley. See the Introduction, Section 11.

I will not spare - I will inflict the proper punishment on every incorrigible offender. It does appear, from all the apostle's threatenings, that he was possessed of a miraculous power, by which he could inflict punishment on offenders; that he could deliver the body to Satan for the destruction of the flesh, that the spirit might be saved in the day of the Lord Jesus, Co1 4:21; Co1 5:5. What he says he told them before probably relates to Co1 4:21 : Shall I come with a rod, etc.

I told you before, and foretell you as if I were present a second time,.... He means, that he had in his former epistle faithfully told them of their evils, and admonished them for them; and now he sends to them a second time before his coming, and again admonishes them, as if he was upon the spot with them; so that they had, as before, three witnesses, also a first and second admonition; which, should they be without success, he must proceed further:

and being absent now, I write to them which heretofore have sinned; before he wrote his first epistle, of which he had information, and had faithfully reproved and admonished them; see Co2 12:21.

And to all other; that might since be drawn into a compliance with sinful practices, through their example; or as the Arabic version renders it, "to the rest of the congregation"; who would be witnesses for him, and against them, that he had admonished them a first, and a second time: and by his present writing declares,

that if I come again; for, not knowing what might fall out to prevent him, though he was bent upon coming, and ready for it, nor what was the will of God about it, he does not choose to be positive in the matter; and therefore writes conditionally, and with a guard, and no doubt with a submission to the divine will:

I will not spare; this was the reason why as yet he had not been at Corinth, because he was willing to spare them; see Co2 1:23 being loath to come to severities, if gentler methods would take effect; but now having used all proper means, he is at a point, aud determined not to spare, but to use his apostolical rod, or that power which the Lord had given him in an extraordinary way, as an extraordinary officer, to punish incorrigible offenders, in such manner as the incestuous person, and Hymenaeus and Philetus had been used by him.

Rather, "I have already said (at my second visit), and tell you (now) beforehand, AS (I did) WHEN I WAS PRESENT THE SECOND TIME, SO also NOW in my absence (the oldest manuscripts omit the 'I write,' which here wrongly follows in English Version Greek text) to them which heretofore have sinned (namely, before my second visit, Co2 12:21), and to all others (who have sinned since my second visit, or are in danger of sinning)." The English Version, "as if I were present the second time," namely, this next time, is quite inconsistent with Co2 13:1, "this is the third time I am coming to you," as Paul could not have called the same journey at once "the second" and "the third time" of his coming. The antithesis between "the second time" and "now" is palpable.

if I come again, &c.--that is, whensoever I come again (Act 20:2). These were probably the very words of his former threat which he now repeats again.