"On the day when their hearing, their sights, and their skins will bear witness against them," referring to their limbs.
Muhammad said: The root of the word is that the skins are a metonymy for the private parts.
﴿يَوْم يشَهِدَ عَلَيْهِمْ سَمْعُهُمْ وَأَبْصَارُهُمْ وَجُلُودُهُمْ﴾ جوارحهم.
قَالَ محمدٌ: وأصل الْكَلِمَة: أَن الْجُلُود كنايةٌ عَن الْفروج.
