The lie of the Old Prophet In the 1 Kings, We have man of God from Judah, who came to Bethel to warn Jeroboam and ends up getting killed on his way out by an Old Prophet who lied to him.

1 Kings 13:18
New International Version (NIV)
18: The old prophet answered, “I too am a prophet, as you are. And an angel said to me by the word of the Lord: ‘Bring him back with you to your house so that he may eat bread and drink water.’” (But he was lying to him.)
23: When the man of God had finished eating and drinking, the prophet who had brought him back saddled his donkey for him.
24: As he went on his way, a lion met him on the road and killed him, and his body was left lying on the road, with both the donkey and the lion standing beside it.

Obviously this is a jerk move on the Prophet's part. Lying to the man of God and getting him killed.
What justifies this man's actions? I have not read anything that points to his punishment for lying. What was the reason for the Prophet's actions?
As far as we can tell, the old prophet wanted some company for a meal. When he hears the man of God reply that the Lord had told him not to have such a meal, he does not believe and is dismissive, as if saying "sure, sure, I'm a prophet too, and I was told to ask you just now". This was a lie: God did not cause the old prophet to choose to lie in this way, God did not tell him to test the man of God by lying, but surely God knew that this old prophet would lie.

The man of God agrees to go with the old prophet, in direct disobedience to what God had told him. He is then killed by a danger that God had warned him against. He chose to disobey God, which is the very definition of sin. We should mourn him, but remember that he is the one most responsible for his own death.

As for the old prophet, he seems to avoid taking responsibility for the grave scandal he caused (scandal being the bringing of another person into sin). When he hears that the man of God was mauled and killed by the lion, he says:


  “It is the man of God who rebelled against the charge of the LORD. The LORD has delivered him to a lion, which mangled and killed him, according to the word which the LORD had spoken to him.”
  (1 Kings 13:26)


Clearly, being a prophet does not mean that one is without sin. Still, while the old prophet seems to publicly declare his own non-involvement, his actions suggest that he feels very serious remorse over what has happened, for he goes to get and then bury the body, and mourns saying "Alas, my brother!", and then instructs his sons that his own body should be placed in the very same grave as the man of God, who he recognizes as a prophet.