1 Kings 2:8-9

8And look, you have with you Shimei the son of Gera, the Benjamite of Bahurim; he is the one who cursed me with a sinister curse the day I went to Mahanaim. But he came down to meet me at the Jordan [on my return], and I swore to him by the Lord, saying, ‘I will not put you to death with the sword.’

9But now do not let him go unpunished, for you are a wise man; and you will know what to do to him, and you will bring his gray head down to Sheol [covered] with blood.”