1 Kings 17:1 - The Popular Commentary by Paul E. Kretzmann

And Elijah ("My God is Jehovah") the Tishbite, a native, so far as can be determined, of Galilee, but having been removed to Gilead, where he lived as a stranger, who was of the inhabitants of Gilead, said unto Ahab, As the Lord God of Israel liveth, before whom I stand, a most solemn oath, emphasizing his position as servant and ambassador of Jehovah, there shall not be dew, which was usually very heavy in Palestine, nor rain these years but according to my word. It was a threat of punishment for the sin of idolatry and at the same time an evidence against the worship of Baal, to whom was ascribed the controlling power of nature. Drought and barrenness were a proof of the impotence of the idol and a direct punishment of God for the sin of idolatry, Leviticus 26:19-20; Deuteronomy 11:16-17.