Sayyiduna Uqbah bin Amir (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "On the Day of Resurrection the sun will come close to the earth, and people will sweat. The sweat of some people will reach their knees, of some (the narrator said: I think he said) their buttocks, of some their shoulders, of some their upper shoulders, and of some it will reach the middle of the mouth." And he (peace and blessings be upon him) gestured with his hand, placing it over his mouth like a bridle. The narrator said: I saw the Messenger of Allah (peace and blessings be upon him) spread his hand out like this: "And some will be completely covered by their sweat." And he (peace and blessings be upon him) gestured by placing his hand on his head.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 14915