Here's the story.
Ahab, the king of Israel, was a follower of Baal, which, of course, Yahweh and Elijah didn't like very much. So Elijah suggested a prayer contest to determine which god was the real God.
Elijah told Ahab to get all the prophets of Baal to meet him on Mt. Carmel. When they arrived, he told them to get a bull, kill it, chop it into pieces, and put the whole bloody mess on some wood. But don't light it on fire. Then ask Baal to light it all on fire.
So the prophets of Baal did that. They prayed and prayed and cut themselves with knives, but nothing happened. Elijah taunted them, saying, "Pray harder! Maybe your god is on a trip or sleeping or something." But still there was no fire.
Elijah did the same thing. He even poured water over it all three times. Then he prayed to God and a fire fell down from heaven and consumed it all, even the surrounding stones.
Then Elijah told the spectators to slaughter the 450 prophets of Baal.
Baal's prophets are four hundred and fifty men. ....
And Elijah said unto them, Take the prophets of Baal; let not one of them escape. And they took them: and Elijah brought them down to the brook Kishon, and slew them there. 1 Kings 18:22, 40
Here's ZJemptv's Mount Carmel Challenge.
Why doesn't anyone try this experiment today? (Skipping the slaughter of the losers.) We could start with believers vs. non-believers, Christians vs. Muslims, Catholics vs. Protestants, etc., until we zoomed in on the correct religious belief. It'd be so simple!
God's next killing: The first God-assisted slaughter of the Syrians