Yahya related to me from Malik from Abu'n Nadr, the mawla of Umar
ibn Ubaydullah, from Abu Salama ibn Abd ar-Rahman that A'isha, the
wife of the Prophet, may Allah bless him and grant him peace, said,
"The Messenger of Allah, may Allah bless him and grant him peace, used
to fast for so long that we thought he would never stop fasting, and
he would go without fasting for so long that we thought he would never
fast again. I never saw the Messenger of Allah, may Allah bless him
and grant him peace, fast for a complete month except for Ramadan, and
I never saw him do more fasting in any one month than he did in
Shaban.'
Muwatta Malik Book 18, Hadith 62