2 Peter 3:11-13, NKJV
Peter previously declared in v.10 that the day of the Lord will come like a thief. When He comes, the heavens and the earth will disappear, or change; everything done in it will be laid bare by fire with a rushing sound.
Here in v.11, he continued the prophecy (vv. 7,10), saying that since all these things will be dissolved, what manner of person ought you to be in holy conduct and godliness, What is the apostle telling believers? He’s telling you that since you know all these things will be dissolved, you ought to spend your time daily living holy and persevering in godliness. While waiting for the Lord’s return, behave in a manner that shows you are set apart and “walking worthy of the calling with which you were called.” (Ephesians 4:1b).
This verse (12) completes the question the apostle asked starting in v.11. As you walk daily in holiness and godliness, earnestly looking for and awaiting the coming of the day of God, Apostle Peter again reminds believers that on this day the heavens will be destroyed by burning, and the elements [the atmospheric heavens, which include the air that we breathe as well as the space that immediately surrounds the earth] will melt with intense heat! Just the same, after the renovation by fire, according to His promise, we look for new heavens and a new earth, God’s new creation, in which righteousness will dwell permanently (v.13).
I don’t know when He is coming, but He said He is, and with me that settles it. Give Him glory!