Charles Ellicott Commentary 1 Kings 18:7

"And as Obadiah was in the way, behold, Elijah met him: and he knew him, and fell on his face, and said, Is it thou, my lord Elijah?" — 1 Kings 18:7 (ASV)

Art thou that ... —The sense is either (as the Septuagint has it) “Is it your very self, my lord Elijah?” or (perhaps more suitably to the context), “You here, my lord Elijah,” when all seek your life? The prophet’s answer is still simpler in its original brevity, “Behold, Elijah!” standing in dignified contrast with the humble and almost servile address of Obadiah, which is clearly the offspring not only of reverence, but of fear.