Matthew Henry on 2 Peter 3:1-4

The purified minds of Christians are to be stirred up, that they may be active and lively in the work of holiness. There will be scoffers in the last days, under the gospel, men who make light of sin, and mock at salvation by Jesus Christ. One very principal article of our faith refers to what only has a promise to rest upon, and scoffers will attack it till our Lord is come. They will not believe that he will come. Because they see no changes, therefore they fear not God, Ps 55:19. What he never has done, they fancy he never can do, or never will do.