But the Day of the Lord will come like a thief. The heavens will disappear with a roar, the elements will be destroyed by fire, and the earth and its works will be laid bare.
10. But the day of the Lord will come. This has been added, that the faithful might be always watching, and not promise to-morrow to themselves. For we all labor under two very different evils — too much haste, and slothfulness. We are seized with impatience for the day of Christ already expected; at the same time we securely regard it as afar off.
We are here told that the Lord is not slack - he does not delay beyond the appointed time; as God kept the time that he had appointed for the delivering of Israel out of Egypt, to a day (Exo 12:41), so he will keep to the time appointed in coming to judge the world.
Commenting on 2 Peter 3:9-10
But the day of the Lord will come as a thief in the night,.... That is, the Lord will come in that day, which he has fixed, according to his promise, than which nothing is more certain; and he will come as a thief in the night: he will come "in the night", which may be literally understood; for as his first coming was in...