I do not know where the Spirit of the LORD may carry you off when I leave you. Then when I go and tell Ahab and he does not find you, he will kill me. But I, your servant, have feared the LORD from my youth.
He fears the Spirit of the LORD may carry Elijah away again, leaving Ahab to kill him despite his lifelong fear of the LORD.
This verse explains why Obadiah hesitates to obey.
1After a long time, in the third year of the drought, the word of the LORD came to Elijah: “Go and present yourself to Ahab, and I will send rain upon the face of the earth.” 2So Elijah went to present himself to Ahab. The famine was severe in Samaria, 3and Ahab summoned Obadiah, who was in charge of the palace. 4(Now Obadiah greatly feared the LORD, for when Jezebel had slaughtered the prophets of the LORD, Obadiah had taken a hundred prophets and hidden them, fifty men per cave, providing them with food and water.) 5Then Ahab said to Obadiah, “Go throughout the land to every spring and every valley. Perhaps we will find grass to keep the horses and mules alive so that we will not have to destroy any livestock.” 6So they divided the land to explore. Ahab went one way by himself, and Obadiah went the other way by himself. 7Now as Obadiah went on his way, Elijah suddenly met him. When Obadiah recognized him, he fell facedown and said, “Is it you, my lord Elijah?” 8“It is I,” he answered. “Go tell your master, ‘Elijah is here!’” 9But Obadiah replied, “How have I sinned, that you are handing your servant over to Ahab to put me to death? 10As surely as the LORD your God lives, there is no nation or kingdom where my lord has not sent someone to search for you. When they said, ‘He is not here,’ he made that kingdom or nation swear that they had not found you. 11And now you say, ‘Go tell your master that Elijah is here!’ 12I do not know where the Spirit of the LORD may carry you off when I leave you. Then when I go and tell Ahab and he does not find you, he will kill me. But I, your servant, have feared the LORD from my youth. 13Was it not reported to my lord what I did when Jezebel slaughtered the prophets of the LORD? I hid a hundred prophets of the LORD, fifty men per cave, and I provided them with food and water. 14And now you say, ‘Go tell your lord that Elijah is here!’ He will kill me!” 15Then Elijah said, “As surely as the LORD of Hosts lives, before whom I stand, I will present myself to Ahab today.”