1 Samuel 18:25-27

25Saul said, ‘Tell David this: The king does not want David to pay money to marry the king's daughter. He can pay for her with the foreskins of 100 dead Philistines. Saul wants David to punish his enemies.’ In this way, Saul thought that he would use the Philistines to kill David.

26Saul's servants told David what Saul wanted. It made David happy to think that he could marry the king's daughter. Before the time for the wedding arrived,

27David and his men left their homes. They went and they killed 200 Philistines. David brought all their foreskins to Saul. David gave them to Saul so that he could marry the king's daughter. So Saul agreed to let David marry his daughter Michal.