Second Peter:

This book, written as a letter to Christians by Simon Peter, tells them to enjoy other people and grow to love them; to beware of false prophets; to not be a slave to sin. There is a warning to not return to sin after becoming Christian, saying that such a person would be worse off than before (2 Peter 2:20), and warning of the old saying that a "dog returns to its vomit," and a "sow that is washed goes back to her wallowing in the mud." (2 Peter 2:22)

The judgment day is described:

1. "...the present heavens and earth are reserved for fire, being kept for the day of judgment and destruction of ungodly men. But...With the Lord a day is like a thousand years, and a thousand years are like a day." (2 Peter 3:7-8)
2. "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 everything in it will be laid bare (i.e., burned up)." (2 Peter 3:10)
3. "...the day of God... will bring about the destruction of the heavens by fire, and the elements will melt in the heat." (2 Peter 3:12).