Sayyiduna Thawban (may Allah be pleased with him) states: The Prophet (peace and blessings be upon him) was asked, and he (peace and blessings be upon him) said: "The molar of the disbeliever will be like Mount Uhud, and the thickness of his skin will be forty cubits, by the cubit of al-Jabbar (that is, Allah Almighty)."
Al-Bazzar recorded it; its chain contains Abbad bin Mansur, who is da'if (weak), though he has been declared trustworthy; the rest of its narrators are thiqat (trustworthy).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب صفة أهل النار / 18610