2 Samuel 14:11

14:11 She replied, “In that case, let the king invoke the name of the Lord your God so that the avenger of blood may not kill! Then they will not destroy my son!” He replied, “As surely as the Lord lives, not a single hair of your son’s head will fall to the ground.”

2 Samuel 14:26

14:26 When he would shave his head – at the end of every year he used to shave his head, for it grew too long and he would shave it – he used to weigh the hair of his head at three pounds according to the king’s weight.