There is no room for fence sitting!
1 Kings 18:17-19 When he saw Elijah, he said to him, "Is that you, you troubler of Israel?" (18) I have not made trouble for Israel, Elijah replied. "But you and your father's family have. You have abandoned the LORD's commands and have followed the Baals. (19) Now summon the people from all over Israel to meet me on Mount Carmel. And bring the four hundred and fifty prophets of Baal and the four hundred prophets of Asherah, who eat at Jezebel's table."
It is amazing that Ahab, as king, was actually quite spineless. He was ordered around by Jezebel and followed her agenda, yet on his first meeting with Elijah he said to him 'Is that you, you troubler of Israel?' He blamed Elijah for the drought which had lasted for 3 รข years. There was nothing growing in the land, and the king and his servant Obadiah were out looking for grass to keep the livestock alive. In other words, because there had been a drought for so long, and there was nothing growing, it was all Elijah's fault! Ahab has no consciousness of his own sin, or his own contribution as to what is happening in the nation of Israel, so he is blaming Elijah.
1 Kings 18:20-21 So Ahab sent word throughout all Israel and assembled the prophets on Mount Carmel. (21) Elijah went before the people and said, "How long will you waver between two opinions? If the LORD is God, follow him; but if Baal is God, follow him." But the people said nothing.
You have three types of people gathered here: Elijah, who is a faithful prophet of the Lord, the 450 false prophets and all the people of Israel. Elijah said to them 'How long will you falter between two opinions? If the Lord is God, follow Him, but if Baal, follow him'. In other words pluralism is not okay. If you remember what was happening in the land, Jezebel had said that it was okay to worship both Yahweh, and Baal. However, she then tried to remove the existence of God from the land and set up Baal worship alone. At this point the people were divided; they thought it was okay to worship Jehovah and also to worship Baal. Then Elijah came and said that they could not have pluralism, they could not worship both. It is either one or the other. If Jehovah is God, then worship Him, but if Baal is God then devote yourself to him. They could no longer sit on the fence. When you look at scripture, Jehovah always separated Himself. He said 'You cannot have any other gods before Me. I have to be completely holy and separate amongst the nation of Israel'. There was no room for any other so-called deities. There was one God, and that was it. It is the same when you get into the New Testament. Jesus didn't claim to be one of the ways; He claimed to be 'The Way'. He said 'I Am The Way, The Truth and The Life, no man comes to the Father but by Me'.
There are many fence sitters in Christianity. For example in American Christianity just about everyone says that they are a born again believer, but have one foot in the world and one foot in the things of the Lord. It is the same here; these people had a foot either side of the fence. So Elijah came and said 'you cannot falter between two opinions. You are double minded, you either serve one or the other. You cannot serve both'. He asked them how long they would falter between two opinions. Now Baal was the god of thunder and he was also the god of fertility. Elijah is saying to these people 'look, we have had a drought here for three and a half years, if Baal is god why have we not had any rain?' 'How long is it going to take you to see that this is a judgement by Jehovah upon the land and that He is showing He has the power over the rain, not Baal'. It is evident that something is happening in the land and he says 'Look, make a decision. It is either one or the other'.
From: The showdown: Elijah vs the prophets of Baal!