1 Kings 13:9

Eat no bread, nor drink water - The reason of the command is evident. The man of God was not to accept the hospitality of any dweller at Bethel, in order to show in a marked way, which men generally could appreciate, God’s abhorrence of the system which Jeroboam had “devised of his own heart.”

Nor turn again by the same way that thou camest - This command seems to have been given simply to test the obedience of the prophet by laying him under a positive as well as a moral obligation.