The Prophet ﷺ said, "The molar of the disbeliever will be like Mount Uhud, his thigh like al-Bayda, his seat in the Fire will span the distance between Qudayd and Mecca, and the thickness of his skin will be forty-two cubits by the cubit of the Giant."
حدثنا حسن حدثنا عبد الرحمن بن عبد الله بن دينار عن زيد بن أسلم عن عطاء بن يسار
عن النبي ﷺ قال ضرس الكافر مثل أحد وفخذه مثل البيضاء ومقعده من النار كما بين قديد إلى مكة وكثافة جلده اثنان وأربعون ذراعا بذراع الجبار
Its isnad is sahih. Muslim narrated it in the Book of Paradise and Hell, may Allah protect us from it, 4/2189, no. 2851, and Tirmidhi, 4/703, no. 2578, in the chapter on the description of Hell, what has been said about the enormity of the people of Hell, both with similar wording, and he said, hasan gharib. Tirmidhi means by this the rarity of the wording of the text, but scholars have held that there is an implied phrase here, namely, by the cubit which the All-Compelling made its measure on the Day of Resurrection.