Sahih Muslim
The Book Pertaining to the Excellent Qualities of the Holy Prophet (may Peace be upon them) and His Companions (Kitab Al-Fadail)
Book Number: 030 / Hadith Number: 5763
Umm Sulaim reported that Allah's Apostle (may peace be upon him) visited her house and (took rest) and she spread a piece of cloth for him and he had had a siesta on it. And he sweated profusely and she collected his sweat and put it in a perfume and in bottles. Allah's Apostle (may peace be upon him) said: Umm Sulaim, what is this? She said: It is your sweat, which I put in my perfume. Allah's Apostle (may peace be upon him) sweated in cold weather when revelation descended upon him.