What does 1 Kings 18:24 mean?

Then you call on the name of your god, and I'll call on the name of the Lord. The God who answers with fire—he's the real God. All the people said, That sounds good. 1 Kings 18:24 - Modern Text Bible

(Elijah proposes a clear test: whichever god sends fire is the true God. The people agree to this challenge.)