1 Kings 13:14

And found him sitting under an oak Being faint and weary with his journey, and possibly with the heat also, (which made him choose to rest in this shady place,) and especially with hunger and thirst, 1 Kings 13:9. And the old prophet might easily guess that this was the prophet from Judah, by his age and carriage, and, it may be, by his prophetic mantle, and by the character which his sons had given of him.