Elijah was receiving instruction directly from the Lord himself and he then set about implementing the Lord’s purpose.

It is noteworthy that after Solomon, more is said about the prophet Elijah than any other person or king in the book of 1 Kings. Elijah is such an influential figure that he appears on the mount of transfiguration with Jesus and Moses (Matt 17:1–3; Mark 9:2–4; Luke 9:28–30). Elijah is often referred to as the prophet of fire, that appellation is no doubt largely attributable to the incident on Mount Carmel. Here, Elijah stands alone as the prophet of the Lord against hundreds of prophets of Baal and Asherah who enjoy royal privileges (1 Kgs 18:19).
Elijah sets the challenge before the people
Elijah sets the challenge before the people, the god that answers by fire, let him be God (1 Kgs 18:24). We learn from this text that the Lord God answered by fire in dramatic fashion (1 Kgs 18:38) consuming the sacrifice that Elijah had immersed in water, whereas the gods of the false prophets failed to respond and their prophets were slain by order of Elijah. The key to understanding this incident, we believe, is contained in the prayer of Elijah, where he confesses aloud in the presence of the people that he has done all these things at the Lord’s command (1 Kgs 18:36).
From the outset of Elijah’s ministry, he was receiving instruction directly from the Lord himself and he then set about implementing the Lord’s purpose, quite unlike any other Old Testament prophet. It is only with Jesus Christ do we see a similar emphasis on doing the Lord’s will. Hence, we have termed this the Covenant of God’s Purpose. In answering by fire, the Lord was conveying to his people that they can know his purpose and be used to execute that purpose. Once again, this is a unilateral covenant delivered by the sovereign grace of God.