The passage you’re probably thinking of is 2 Peter 3:6–7 , which says the present heavens and earth are “reserved for fire” by the same word of God that once brought judgment by water.

Another closely related verse is Revelation 22:18–19 , where the Bible says not to add to or take away from the words of the prophecy; people sometimes connect that with the idea that “the Word” remains after the end.

Most likely reference

  • 2 Peter 3:7 : the world is “stored up for fire” until the day of judgment.
  • 2 Peter 3:11–12 : this section asks what kind of people believers should be, since everything will be dissolved.
  • Revelation 22:18–19 : warns against altering the words of the prophecy.

Important nuance

The Bible does not clearly say in one verse, “after the final fire all that is left is the Word.” That wording sounds like a summary or interpretation drawn from passages about judgment, fire, and the permanence of God’s word.

Simple answer

If you want the clearest biblical place, start with 2 Peter 3:6–7. If your focus is on the final authority of Scripture, also read Revelation 22:18–19.