Obey the word of the Lord an keep the command the Lord gave me

1 King 13:20-28
While they were sitting at the table, the word of the Lord came to the old prophet who had brought him back. He cried out the the man of Go who had come from Judah, "This is what the Lord says: You have defied the word of the Lord and have not kept the command the Lord your God gave you. You came back an ate bread and drank water in the place where he told you not to eat or drink. Therefore your body will not be buried in the tomb of your fathers.
As he went on his way, a lion met him on the road and killed him, and his body was thrown down on the road, with both the donkey and the lion standing beside it.
Why?
The lion killed the old prophet is not for hungry but arranged by the Lord to kill him.
The prophet from Judah is wrong to accept the old prophet's word when it contradicts God's own word to him. The point the writer makes is that God must be obeyed. The prophet's death is a sign to Jeroboam an Israel of the severity with which God deals with disobedience.
A lion: Lion roamed Palestine, particularly the Jordan Valley, until the Middle Ages. Here the strange sight of the lion standing by its prey, but leaving both the body and  the ass untouched, arks the event as having special significance. It is a 'sign' to Israel.
Christian comprised with the world will bring disaster to us.
How?
Discern the word of God is an important thing. It is the way we have to keep God's in my life.