C. F. Keil and Franz Delitzsch on 1 Kings 19:9

1Ki 19:9 Appearance of God at Horeb. - 1Ki 19:9. When Elijah arrived at Horeb, he went into the cave (the definite article in המּערה, with the obvious connection between the appearance of God, which follows here, and that described in Exo 33:12., points back to the cleft in the rock, נקרת הצּוּר) in which Moses had stood while the glory of Jehovah passed by (see at Exo 33:22), and there he passed the night. And behold the word of the Lord came to him (in the night): “What doest thou here, Elijah?” This question did not involve a reproof, as though Elijah had nothing to do there, but was simply intended to lead him to give utterance to the thoughts and feelings of his heart.