Albert Barnes Commentary 2 Kings 1:9

"Then [the king] sent unto him a captain of fifty with his fifty. And he went up to him: and, behold, he was sitting on the top of the hill. And he spake unto him, O man of God, the king hath said, Come down." — 2 Kings 1:9 (ASV)

Then the king sent to him - that is, in order to seize and punish him. Compare 1 Kings 18:10; 1 Kings 22:27.