Yahya said: It reached us that the Zaqqum tree grows at the sixth gate of Hell upon a rock of fire. Beneath it is a spring of scalding, black, and thick water. Hunger is then inflicted upon one of them, so he is driven to it and eats from it until he fills his belly. It boils in his belly like the boiling of scalding fluid. He then asks for a drink to cool his insides, so he descends from the tree to that spring which flows from beneath the rock; above it is the Zaqqum, and beneath it is the scalding fluid. His feet slip, and he falls onto his back and side, being roasted upon it just as a fish is roasted on a skillet. The keepers drag him by his face, and he descends toward that spring. He does not reach it until the flesh of his face has fallen away. When he reaches that spring, the keepers give him a drink in a vessel, and when it [comes near his face], his face is roasted. When he places it upon his lips, his lips are severed, and his molars and canines fall out from its heat. When it settles in his belly, it expels whatever was in his belly through his rectum.

Tafsir of Surat al-Rahman from verse 46 to verse 61.