Albert Barnes Commentary 1 Kings 18:41

"And Elijah said unto Ahab, Get thee up, eat and drink; for there is the sound of abundance of rain." — 1 Kings 18:41 (ASV)

Get thee up, eat and drink - Ahab had descended the hillside with Elijah and witnessed the slaughter of the priests. Elijah now told him to ascend the hill again and partake of the feast that was already prepared, which always followed a sacrifice.

There is a sound of abundance of rain - Either the wind, which in the East usually heralds rain, had begun to rise and sighed through the forests of Carmel, or perhaps the sound was simply in the prophet’s ears—a mysterious intimation to him that the drought was to end and that rain would come that day.