'Foreskins' in the Bible

And Saul said, Thus shall ye say to David: The king does not desire any dowry, but a hundred foreskins of the Philistines, to be avenged of the king's enemies. But Saul thought to make David fall by the hand of the Philistines.

when David arose and went, he and his men, and smote of the Philistines two hundred men; and David brought their foreskins, and they delivered them in full to the king, that he might be the king's son-in-law. And Saul gave him Michal his daughter as wife.