R. Elazar b. Azaryah says: Repulsive is the foreskin, by which the wicked are demeaned, viz. (Jeremiah 9:25) "for all the nations are uncircumcised, and all the house of Israel is uncircumcised of heart."
The Foreskin Is So Repulsive That Scripture Uses It to Shame the Wicked
Mekhilta Tractate Amalek 3:19