Charles Spurgeon Commentary 1 Kings 18:27-31

"And it came to pass at noon, that Elijah mocked them, and said, Cry aloud; for he is a god: either he is musing, or he is gone aside, or he is on a journey, or peradventure he sleepeth and must be awaked. And they cried aloud, and cut themselves after their manner with knives and lances, till the blood gushed out upon them. And it was so, when midday was past, that they prophesied until the time of the offering of the [evening] oblation; but there was neither voice, nor any to answer, nor any that regarded. And Elijah said unto all the people, Come near unto me; and all the people came near unto him. And he repaired the altar of Jehovah that was thrown down. And Elijah took twelve stones, according to the number of the tribes of the sons of Jacob, unto whom the word of Jehovah came, saying, Israel shall be thy name." — 1 Kings 18:27-31 (ASV)

For he meant this day to prove that God was God of the twelve tribes — not of himself and his tribe, but of all the families of Israel.