Albert Barnes Commentary 1 Kings 13:14

"And he went after the man of God, and found him sitting under an oak; and he said unto him, Art thou the man of God that camest from Judah? And he said, I am." — 1 Kings 13:14 (ASV)

Under an oak. This phrase literally means “under the oak” or “the terebinth tree.” It refers to a specific, well-known tree of this kind that stood by itself near Bethel, which the author assumed his readers would recognize.