'Foreskins' in the Bible

Saul said, "This is what you are to tell David, "The king desires no bride price except 100 Philistine foreskins to take vengeance on the king's enemies.'" Now Saul thought he would cause David to die at the hand of the Philistines.

David got up, went out with his men, and struck down 200 Philistine men. David brought their foreskins and gave them all to the king so he could become the king's son-in-law. So Saul gave him his daughter Michal as a wife.