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: 5761
Anas b. Malik reported that Allah's Apostle (may peace be upon him) used to come to our house and there was perspiration upon his body. My mother brought a bottle and began to pour the sweat in that. When Allah's Apostle (may peace be upon him) got up he said: Umm Sulaini, what is this that you are doing? Thereupon she said: That is your sweat which we mix in our perfume and it becomes the most fragrant perfume.