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 (2 Cor. 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, 2 Cor. 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 (Matt. 17:16) concerning the manner how Christians should deal with offenders before they proceed to extremity than to the law of Moses (Deut. 17:6; 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, 2 Cor. 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 (2 Cor. 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 (2 Cor. 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 (2 Cor. 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 (2 Cor. 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!