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: 5797
'A'isha reported that Allah's Messenger (may peace be upon him) died when he had attained the age of sixty-three. And a hadith like this had been transmitted on the authority of Sa'id b. Musayyib.