9. The Lord knoweth. What first offends the weak is, that when the faithful anxiously seek aid, they are not immediately helped by God; but on the contrary he suffers them sometimes as it were to pine away through daily weariness and languor; and secondly, when the wicked grow wanton with impunity and God in the meantime is silent, as though he connived at their evil deeds. This double offense Peter now removes; for he testifies that the Lord knows when it is expedient to deliver the godly from temptation. By these words he reminds us that this office ought to be left to him, and that therefore we ought to endure temptations, and not to faint, when at any time he defers his vengeance against the ungodly.
This consolation is very necessary for us, for this thought is apt to creep in, “If the Lord would have his own to be safe, why does he not gather them all into some corner of the earth, that they may mutually stimulate one another to holiness? why does he mingle them with the wicked by whom they may be defiled?” But when God claims to himself the office of helping, and protecting his own, that they may not fail in the contest, we gather courage to fight more strenuously. The meaning of the first clause is, that this law is prescribed by the Lord to all the godly, that they are to be proved by various temptations, but that they are to entertain good hope of success, because they are never to be deprived of his aid and help.
And to reserve the unjust. By this clause he shews that God so regulates his judgments as to bear with the wicked for a time, but not to leave them unpunished. Thus he corrects too much haste, by which we are wont to be carried headlong, especially when the atrocity of wickedness grievously wounds us, for we then wish God to fulminate without delay; when he does not do so, he seems no longer to be the judge of the world. Lest, then, this temporary impunity of wickedness should disturb us, Peter reminds us that a day of judgment has been appointed by the Lord; and that, therefore, the wicked shall by no means escape punishment, though it be not immediately inflicted.
There is an emphasis in the word reserve, as though he had said, that they shall not escape the hand of God, but be held bound as it were by hidden chains, that they may at a certain time be drawn forth to judgment. The participle κολαζομένους, though in the present tense, is yet to be thus explained, that they are reserved or kept to be punished, or, that they may be punished. For he bids us to rely on the expectation of the last judgment, so that in hope and patience we may fight till the end of life.