The Apostle Peter reminds us that the Lord's promise about His return is not slack. People will say it has been thousands of years, "Where is He?" He wants them to know that the Lord once before came and wiped away the sin of the world with the flood and will come again and wipe it out with fire. As a result we need to live right and hope in this. He exhorts us to be found diligent by the Lord when He does return.