Charles Spurgeon Commentary 1 Kings 18:19

"Now therefore send, and gather to me all Israel unto mount Carmel, and the prophets of Baal four hundred and fifty, and the prophets of the Asherah four hundred, that eat at Jezebel`s table." — 1 Kings 18:19 (ASV)

He knew how many there were of them. The man's heart was so engaged in this battle for God against idols, that he had counted all his adversaries.