After a long time, in the third year, the word of the LORD came to Elijah: "Go and present yourself to Ahab, and I will send rain on the land." So Elijah went to present himself to Ahab. Now the famine was severe in Samaria, and Ahab had summoned Obadiah, who was in charge of his palace. (Obadiah was a devout believer in the LORD. While Jezebel was killing off the LORD's prophets, Obadiah had taken a hundred prophets and hidden them in two caves, fifty in each, and had supplied them with food and water.) Ahab had said to Obadiah, "Go through the land to all the springs and valleys. Maybe we can find some grass to keep the horses and mules alive so we will not have to kill any of our animals." So they divided the land they were to cover, Ahab going in one direction and Obadiah in another.
As Obadiah was walking along, Elijah met him. Obadiah recognized him, bowed down to the ground, and said, "Is it really you, my lord Elijah?"
"Yes," he replied. "Go tell your master, 'Elijah is here.' "
"What have I done wrong," asked Obadiah, "that you are handing your servant over to Ahab to be put to death? As surely as the LORD your God lives, there is not a nation or kingdom where my master has not sent someone to look for you. And whenever a nation or kingdom claimed you were not there, he made them swear they could not find you. But now you tell me to go to my master and say, 'Elijah is here.' I don't know where the Spirit of the LORD may carry you when I leave you. If I go and tell Ahab and he doesn't find you, he will kill me. Yet I your servant have worshiped the LORD since my youth. Haven't you heard, my lord, what I did while Jezebel was killing the prophets of the LORD ? I hid a hundred of the LORD's prophets in two caves, fifty in each, and supplied them with food and water. And now you tell me to go to my master and say, 'Elijah is here.' He will kill me!"
Elijah said, "As the LORD Almighty lives, whom I serve, I will surely present myself to Ahab today."

So Obadiah tells Ahab. When he saw Elijah, he said to him, "Is that you, you troubler of Israel?" And Elijah says, ''I'm not the one making trouble, you and you're fathers are.''

Then Elijah said to them, "I am the only one of the LORD's prophets left, but Baal has four hundred and fifty prophets. Get two bulls for us. Let them choose one for themselves, and let them cut it into pieces and put it on the wood but not set fire to it. I will prepare the other bull and put it on the wood but not set fire to it. Then you call on the name of your god, and I will call on the name of the LORD. The god who answers by fire—he is God."Then all the people said, "What you say is good."

So they do that. Of course, Elijah's offering catches fire and the other poeples didn't. I think you would have to be pretty faithful to God to just say something and God will do it. How do you know that he will?