At the Lord's command a prophet from Judah went to Bethel and arrived there as Jeroboam stood at the altar to offer the sacrifice.
Following the Lord's command, the prophet denounced the altar: "O altar, altar, this is what the Lord says: A child, whose name will be Josiah, will be born to the family of David. He will slaughter on you the priests serving at the pagan altars who offer sacrifices on you, and he will burn human bones on you." 1
References for 1 Kings 13:2
And the prophet went on to say, "This altar will fall apart, and the ashes on it will be scattered. Then you will know that the Lord has spoken through me."
When King Jeroboam heard this, he pointed at him and ordered, "Seize that man!" At once the king's arm became paralyzed so that he couldn't pull it back.
The altar suddenly fell apart and the ashes spilled to the ground, as the prophet had predicted in the name of the Lord.
King Jeroboam said to the prophet, "Please pray for me to the Lord your God, and ask him to heal my arm!" The prophet prayed to the Lord, and the king's arm was healed.