Sahih Bukhari Volume 003, Book 031, Hadith Number 194.

Narated By Humaid : I asked Anas about the fasting of the Prophet. He said "Whenever I liked to see the Prophet fasting in any month, I could see that, and whenever I liked to see him not fasting, I could see that too, and if I liked to see him praying in any night, I could see that, and if I liked to see him sleeping, I could see that, too." Anas further said, "I never touched silk or velvet softer than the hand of Allah's Apostle and never smelled musk or perfumed smoke more pleasant than the smell of Allah's Apostle."