If sometime God grant to them repentance This expression, "If sometime," or "If perhaps," points out the difficulty of the case, as being nearly desperate or beyond hope. Paul therefore means that even towards the most unworthy we must exercise meekness; and although at first there be no appearance of having gained advantage, still we must make the attempt. For the same reason he mentions that "God will grant it." Since the conversion of a man is in the hand of God, who knows whether they who today appear to be unteachable shall be suddenly changed by the power of God, into other men? Thus, whoever shall consider that repentance is the gift and work of God, will cherish more earnest hope, and, encouraged by this confidence, will bestow more toil and exertion for the instruction of rebels. We should view it thus, that our duty is, to be employed in sowing and watering, and, while we do this, we must look for the increase from God. (1-Corinthians 3:6.) Our labors and exertions are thus of no advantage in themselves; and yet, through the grace of God, they are not fruitless. To the knowledge of the truth We may learn from this what is the actual repentance of those who for a time were disobedient to God; for Paul declares that it begins with "the knowledge of the truth." By this he means that the understanding of man is blinded, so long as it stands out fiercely against God and his doctrine.

In meekness instructing those that oppose themselves - That is, those who embrace error, and array themselves against the truth. We are not to become angry with such persons, and denounce them at once as heretics. We are not to hold them up to public reproach and scorn; but we are to set about the business of patiently "instructing them." Their grand difficulty, it is supposed in this direction, is, that they are ignorant of the truth. Our business with them is, "calmly to show them what the truth is." If they are angry, we are not to be. If they oppose the truth, we are still calmly to state it to them. If they are slow to see it, we are not to become weary or impatient. Nor, if they do not embrace it at all, are we to become angry with them, and denounce them. We may pity them, but we need not use hard words. This is the apostolic precept about the way of treating those who are in error; and can any one fail to see its beauty and propriety? Let it be remembered, also, that this is not only beautiful and proper in itself; it is the wiseST course, if we would bring others over to our opinions. You are not likely to convince a man that you are right, and that he is wrong, if you first make him angry; nor are you very likely to do it, if you enter into harsh contention. You then put him on his guard; you make him a party, and, from self-respect, or pride, or anger, he will endeavor to defend his own opinions, and will not yield to yours. "Meekness" and "gentleness" are the very best things, if you wish to convince another that he is wrong. With his heart first, and then modestly and kindly show him "what the truth is," in as few words, and with as unassuming a spirit, as possible, "and you have him."
If God peradventure will give them repentance, - Give them such a view of the error which they have embraced, and such regret for having embraced it, that they shall be willing to admit the truth. After all our care in teaching others the truth, our only dependence is on God for its success. We cannot be absolutely certain that they will see their error; we cannot rely certainly on any power which argument will have; we can only hope that God may show them their error, and enable them to see and embrace the truth; compare Acts 11:18. The word rendered "peradventure," here - μήποτε mēpote - means, usually, "not even, never;" and then, "that never, lest ever" - the same as "lest perhaps." It is translated "lest at any time," Matthew 4:6; Matthew 5:25; Matthew 13:15; Mark 4:12; Luke 21:34; "lest," Matt, Luke 7:6; Luke 13:29; Luke 15:32; "et al.: lest haply," Luke 14:12; Acts 5:39. It does not imply that there was any CHance about what is said, but rather that there was uncertainty in the mind of the speaker, and that there was need of caution LesT something should occur; or, that anything was done, or should be done, to prevent something from happening.
It is not used elsewhere in the New Testament in the sense which our translators, and all the critics, so far as I have examined, give to it here - as implying A hope that God would give them repentance, etc. But I may be permitted to suggest another interpretation, which will accord with the uniform meaning of the word in the New Testament, and which will refer the matter to those who had embraced the error, and not to God. It is this: "In meekness instructing 'those that oppose themselves' (ἀντιδιατιθεμένους antidiatithemenous) 'lest' - μήποτε mēpote - God should give them repentance, and they should recover themselves out of the snare of the devil," etc. That is, they put themselves in this posture of opposition so that they shall not be brought to repentance, and recover themselves. They do it with a precautionary view that they may not be thus brought to repentance, and be recovered to God. They take this position of opposition to the truth, intending not to be converted; and this is the reason why they are not converted.

Those that oppose - Αντιδιατιθεμενους. This seems to refer to those who opposed the apostle's authority; and hence the propriety of the allusion to the rebellion of Korah and his company. See observations at the end of the chapter.
If God peradventure - He was to use every means which he had reason to believe God might bless; and the apostle intimates that, bad as they were, they were not out of the reach of God's mercy.

In meekness instructing those that (k) oppose themselves; if God peradventure will give them repentance to the acknowledging of the truth;
(k) He means those who do not yet see the truth.

In meekness instructing those that oppose themselves,.... To the truth; resist it and deny it; or contradict some other tenets and principles of theirs, or the Scriptures, which they themselves allowed to be the word of God, and the rule of faith and practice, and so are self-convinced and self-condemned. These are to be instructed, being ignorant, and in a tender and gentle manner, though very perverse and obstinate.
If God peradventure will give them repentance to the acknowledging of the truth: repentance here designs a repentance of errors in principle, a change of mind upon conviction, and such as issues in a free and ingenuous confession, and acknowledgment of the truth before opposed; and such a repentance is the gift of God: it is he that opens the eyes of the understanding, and works conviction in the mind, and leads into all truth, as it is in Jesus; and induces men to repent of their errors, confess their mistakes, and own the truth; even as repentance of evil practices is not owing to the power of men, nor to the bare influence of means, but to the efficacious grace of God, it being a grant from him. And though this is not certain, that God will give repentance to such contradictors and blasphemers of his Gospel; yet as it is his will, that all his chosen ones should come to repentance, and that some of all sorts should be saved, and come to the knowledge of the truth; and seeing these things have been brought about under and by the ministry of the word, it is an encouragement to the ministers of the Gospel to continue their instructions in the manner here directed.

instructing--Greek, "disciplining," instructing with correction, which those who deal in "uninstructive" or "undisciplined questions" need (see on 2-Timothy 2:23; 1-Timothy 1:20).
those that oppose themselves--Greek, "oppositely affected"; those of a different opinion.
if . . . peradventure--Greek, "if at any time."
repentance--which they need as antecedent to the full knowledge (so the Greek for 'acknowledgment') of the truth" (1-Timothy 2:4), their minds being corrupted (2-Timothy 3:8), and their lives immoral. The cause of the spiritual ignorance which prompts such "questions" is moral, having its seat in the will, not in the intellect (John 7:17). Therefore repentance is their first need. That, not man, but God alone can "give" (Acts 5:31).

In meekness - He has often need of zeal, always of meekness. If haply God - For it is wholly his work. May give them repentance - The acknowledging of the truth would then quickly follow.