Verses with the word foreskins in the Old Testament (5 verses):
And Joshua made him sharp knives, and circumcised the children of Israel at the hill of the foreskins.
1 Samuel 18:25
And Saul said, Thus shall ye say to David, The king desireth not any dowry, but an 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.
1 Samuel 18:27
Wherefore David arose and went, he and his men, and slew of the Philistines two hundred men; and David brought their foreskins, and they gave them in full tale to the king, that he might be the king's son in law. And Saul gave him Michal his daughter to wife.
2 Samuel 3:14
And David sent messengers to Ishbosheth Saul's son, saying, Deliver me my wife Michal, which I espoused to me for an hundred foreskins of the Philistines.
Circumcise yourselves to the LORD, and take away the foreskins of your heart, ye men of Judah and inhabitants of Jerusalem: lest my fury come forth like fire, and burn that none can quench it, because of the evil of your doings.