Sahih Muslim Book 40, Hadith Number 6815.
Chapter : The description of hell and the intensity of its heat and torments.
Samura b. Jundub reported Allah’s Apostle (may peace -be upon him) as saying: There will be some to whose ankles the fire will reach, some to whose knees, some to whose waist the fire will reach, and some to whose collar-bone the fire will reach.