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!

This is the third time I am coming to you - These words are nearly the same with those Co2 12:14; and probably refer to the purpose which he had twice before formed of seeing them. But the latter clause seems to attach a different meaning to the passage; at least so it has been understood by some learned men.

Schoettgen thus interprets the whole: the first coming of the apostle to Corinth was when he personally visited them, and there founded the Christian Church. By his second coming we are to understand his first epistle to them; and, by his being now ready to come to them the third time, we are to understand this second epistle, which he was then going to send them. These were the two witnesses, and the apostle the third, which he gave to the Corinthians concerning the truth of his own ministry, or the falsity of the ministry of the pretended apostle.

Calmet contends that the apostle had been twice before at Corinth, and that he now purposed to go a third time; and that these visits were the two or three witnesses to which the apostle appeals.

Dr. Lightfoot thinks that the two or three witnesses were Stephanas, Fortunatus, and Achaicus, sent to assure them of his coming. But this opinion cannot be supported.

With respect to the two or three witnesses establishing the subject, Dr. Whitby says. "Though these words seem to be cited from Deu 19:15, rather than from Mat 18:16, it being rare to find this apostle citing any thing from the New Testament, without calling it an ordinance of the Lord, yet it is probable that he here alludes to the practice there prescribed for the reclaiming of offenders. And then his first epistle being written with this introduction: Paul an apostle, and Sosthenes; his second thus: Paul and Timotheus; may pass for two or three witnesses; and his presence the third time in person, to exercise his censures on those offenders, before the body of the Church, may bear a fair resemblance to our Lord's prescription in the above case: If thy brother offend," etc. - So far Whitby. See my notes on Mat 18:16 (note).

This is the third time I am coming to you,.... Or "am ready to come to you", as the Alexandrian copy reads, as in Co2 12:14. Though he had been as yet but once at Corinth, and is to be reckoned and accounted for, either after this manner; he had been "once" with them when he first preached the Gospel to them, and was the means of their conversion, and laid, the foundation of their church state, of which there is some account in Act 18:1 he came to them a "second" time, by writing his first epistle, when he desired to be considered by them, as though he was present with them, Co1 5:3 and now a "third" time by this second epistle, in which he also speaks as if he was among them, see the following verse; or else in this way, he had been actually in person with them one time, and had been about to come in purpose and preparation a "second" time, but was prevented, and now was just ready a "third" time to set forward in his journey to them; see Co2 12:14 and so the Syriac version reads it here, "this is the third time that I am ready to come to you", and which our version also favours. The Alexandrian copy and some others, the Complutension edition, the Vulgate Latin and Ethiopic versions, read, "behold, this third time", &c. in order to raise and fix their attention to what he was saying, or about to say:

in the mouth of two or three witnesses shall every word be established; referring to Deu 19:15 which he applies much in the same manner Christ does in Mat 18:16 and which it is probable he had in view; signifying hereby, that he proceeded in a judicial way, according to due form of law, and in such a manner as Christ had directed; and that they were to look upon his several comings in the sense now explained, to be as so many witnesses, whereby the several charges exhibited against them were fully attested and confirmed, so that things were now ripe for judgment, and for a final sentence to pass upon them.