Elijah was like "Why are you guys divided between serving God and Baal? Let's have a test! Bring us some bulls and put them on the altars and whichever God answers with fire, he is God." So they brought bulls and put them on the altars and the priests of Baal cut themselves and prayed to Baal, but of course he didn't answer. But Elijah poured water on his sacrifice and prayed to God and fire came down and burned up everything around the altar: the water, the sacrifice, the wood, everything.