The reign of Ahab as king of Israel, as begins in 1 Kings 16:28, begins a further decline in the religion of the northern tribes. Israel had already struggled with the institutionalized worship of the golden calves. But Ahab married a Phoenician woman from Sidon who worshipped Baal, the storm god. Ahab converted to her religion and institutionalized it in Israel, building a temple and altar and worshipping Baal. He also built monuments to Asherah, the goddess of fertility. These were both part of the pantheon of gods worshipped in various Semitic countries around Israel.
So God (Yahweh) went on the attack through the prophet Elijah. First, he withheld rain from Israel until Elijah decreed it. He therefore said, Yahweh, not Baal, is in control of the weather. Second, he sent Elijah into enemy territory, Sidon, to live with the widow. There, he produced food with no rain or crops, showing that he was God not only of Israel but of all the earth, even Sidon. Third, he restored life to a child, showing his power over human life itself. And, he made a convert on enemy soil.
This is only round one of the battle between Yahweh and Baal. But this round went to the LORD.
"The earth is the LORD'S and everything in it. The world and all its people belong to him." Psalm 24:1