Charles Ellicott Commentary 1 Kings 18:24

"And call ye on the name of your god, and I will call on the name of Jehovah; and the God that answereth by fire, let him be God. And all the people answered and said, It is well spoken." — 1 Kings 18:24 (ASV)

And call you on the name of your gods. — This gift of a “sign from heaven”—not unfamiliar to Israelite experience (1 Chronicles 21:26; 2 Chronicles 7:1)—which, as our Lord teaches us (Matthew 12:38–39; Matthew 16:1–4), may not be craved or demanded as a ground of faith, is, like all other miracles, granted unasked when it is seen by God’s wisdom to be needed, in order to startle an ignorant and misguided people into serious attention to a message from heaven.

In this instance, the worship of Baal was a worship of the power of Nature, impersonated perhaps in the sun; and the miracle therefore entered (so to speak) the visible sphere, especially usurped in his name, in order to claim it for the Lord Jehovah.