C. F. Keil and Franz Delitzsch on 1 Kings 18:30-39

1Ki 18:30-39 Elijah’s sacrifice. - As no answer came from Baal, Elijah began to prepare for his own sacrifice. 1Ki 18:30. He made the people come nearer, that he might have both eye-witnesses and ear-witnesses present at his sacrifice, and restored the altar of Jehovah which was broken down. Consequently, there was already an altar of Jehovah upon Carmel, which either dated from the times anterior to the building of the temple, when altars of Jehovah were erected in different places throughout the land (see at 1Ki 3:2), or, what is more probable, had been built by pious worshippers belonging to the ten tribes since the division of the kingdom (Hengstenberg, Dissertations on the Pentateuch, vol. i. p. 183, trans.), and judging from 1Ki 19:10, had been destroyed during the reign of Ahab, when the worship of Baal gained the upper hand.