1 Kings 2:8-9

8Remember that Shimei is still there to give you trouble. He is the son of Gera who came from Bahurim, and he belonged to Benjamin's tribe. When I went to Mahanaim, he prayed that terrible things would happen to me. But when he came to meet me at the Jordan River, I made a promise to him. I promised him in the Lord's name that I would not punish him with death.

9But remember that he is guilty! You are a wise man, so you will know what to do to him. Even if he is an old man, make sure that he has a violent death.’