´Al-Hasan said:` "While he was on the pulpit – the pulpit of Al-Basrah – `Utbah bin Ghazwain narrated that the Messenger of Allah (s.a.w) said: “Indeed a giant rock can be thrown from the brink of Hell and it will continue to fall into it for seventy years without reaching the bottom of it.”.He said: “`Umar used to say:'Increase in your remembrance of the Fire, for its heat is extreme, its bottom is distant, and its whips are of Iron.'” (Sahih)
Hadith Referenceسنن ترمذي / كتاب صفة جهنم عن رسول الله صلى الله عليه وسلم / 2575
Hadith Gradingالألبانی:صحيح، الصحيحة (1612)
Hadith Takhrij«صحیح مسلم/الزہد 1 (2967) ، سنن ابن ماجہ/الزہد 12 (4156) (مختصراً جداً) ( تحفة الأشراف : 9757) ، و مسند احمد (4/174) ، (5/61) (صحیح)»