1 Samuel 18:25

An hundred foreskins: these he desires rather than their heads; partly, for the greater convenience of bringing them, and presenting them before him; partly, to cover his malice against David with a pretence of zeal for God, and for his people, and for the covenant of circumcision; and partly, that the Philistines might be the more enraged against David for this reproachful and barbarous usage of them, and might therefore watch all opportunities to destroy him.