What does 2 Peter 3:10 mean?

Peter has been answering the false teachers who are leading people away from the truth about Christ. They ask, "Where is Jesus? He promised to return as judge, but He hasn't come. He isn't coming." In the previous verses, Peter showed that God is not slow or late, but that He has been patient in order to make room for as many as possible to come to repentance and turn to Him through faith in Christ.

Now, though, Peter insists that the day of the Lord will come. That coming will be sudden and without warning. Peter is quoting Jesus Himself here, who promised that He would return as unexpectedly as a thief breaking into an unguarded house in the dead of night (Matthew 24:42–44; Revelation 3:3; Revelation 16:15). And when the moment finally comes, catastrophic destruction will follow.

Christian teaching on how the end times will unfold is widely varied. Scholars and theologians studying the prophecies of the Old and New Testaments have reached differing conclusions about the exact order of events. While there are differences in these specific details, Christians on the whole believe what Peter writes here, as part of the revealed Word of God. That is, that Jesus will return. And, at some point, God will judge the sins of humanity by bringing destruction on the earth with fire.

The heavens mentioned here include the sky and perhaps the stars, not the "heaven" of God. The sky will disappear in a roar or a whoosh. The Greek word rhoizēdon implies the rushing or crackling sound of a massive fire. Similarly, the elements or heavenly bodies—either meaning the building blocks of all life, or the stars—will be consumed by fire.

In the end, the earth and everything done on it will be "burned up" or "laid bare" or "exposed." Apparently, it's hard to know what the word used here means exactly. In any case, God's judgment will have come and the destruction will be immense.