In this chapter, we find that God sent an unnamed "man of God" out of Judah into Israel to rebuke Jeroboam because of his wicked ways. The man of God prophesied about a coming king named Josiah. He told the NAME of a future king of Judah & what he would do. But the prophecy didn't come to pass until over 3 centuries later (II Kings 23:16). When Jeroboam heard the words of the man of God, he was offended. But, despite a significant miracle in his presence, Jeroboam remained in his sin (I Kings 13:33).
Now, one amazing thing about this is that God was relatively lax with Jeroboam, but incredibly strict with the man of God. God had instructed his messenger not to do anything during his mission into Israel except what he had been commanded to do. Specifically, he wasn't even supposed to pause for a meal. And, when Jeroboam invited him home for supper, the man of God prudently refused. However, on his way home, an old prophet lied to him and convinced him that God had changed his orders. Well, the man of God paid for his disobedience in this small matter. He paid for it with his life. A lion killed him after he went aside from his mission. God's words are never to be taken lightly. When God makes a decree, we had better take heed.