Sahih Muslim
The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqaiq)
Book Number: 042 / Hadith Number: 7084
'A'isha reported Allah's Messenger (may peace be upon him) as saying: Never did Allah's Messenger (may peace be upon him) eat to his fill the bread of wheat for three successive days until he had run the course of his life.