1 Kings 2:5-6

5Moreover thou knowest also what Joab the son of Zeruiah did to me, and what he did to the two captains of the armies 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 belt that was about his loins, and in his shoes that were on his feet.1

6Do therefore according to thy wisdom, and let not his gray head go down to the grave in peace.