1 Kings 2:5-9

5And thou knowest also what Joab the son of Zeruiah did to me, what he did to the two captains of the hosts of Israel, to Abner the son of Ner, and to Amasa the son of Jether, whom he slew, and shed the blood of war in peace, and put the blood of war upon his girdle that was about his loins, and upon his sandals that were on his feet.

6And thou shalt do according to thy wisdom, and not let his hoar head go down to Sheol in peace.

7But shew kindness to the sons of Barzillai the Gileadite, and let them be of those that eat at thy table; for so they came up to me when I fled because of Absalom thy brother.

8And behold, there is with thee Shimei the son of Gera, the Benjaminite of Bahurim, who cursed me with a grievous curse in the day that I went to Mahanaim; but he came down to meet me at the Jordan, and I swore to him by Jehovah saying, I will not put thee to death with the sword.

9And now hold him not guiltless; for thou art a wise man, and thou shalt know what thou oughtest to do to him; but bring his hoar head down to Sheol with blood.