John Gill Commentary 1 Kings 18:6

"So they divided the land between them to pass throughout it: Ahab went one way by himself, and Obadiah went another way by himself." — 1 Kings 18:6 (ASV)

So they divided the land between them, to pass through it.

And one took one part, and the other the other part: Ahab went one way by himself, and Obadiah went another way by himself.

Ahab not caring to trust any but Obadiah, who he knew was a faithful man, lest they should be bribed by those that had grass not to discover it.