2 Samuel 21:15-17

Now the Philistines were at war again with Israel. David went down with his servants, and as they fought against the Philistines, David became weary. Then Ishbi-benob, who was among the descendants of the giant, the weight of whose spear was three hundred shekels (six pounds) of bronze, was armed with a new sword, and he intended to kill David. But Abishai the son of Zeruiah came to David’s aid, and struck and killed the Philistine. Then David’s men swore to him, “You shall not go out again with us to battle, so that you do not extinguish the lamp of Israel.”