Amr bin 'Uthman عمرو بن عثمان بن عفان · The Book of Fasting

"The Prophet used to fast Shaban." '

"The Messenger of Allah went out to Makkah in the year of the Conquest in Ramadan. He fasted until he reached Kura Al-Ghamim, and the people fast, so he called for a vessel of water after 'Asr and drank it while the people were looking on. Then some of the people broke their fast and some continued to fast. He heard that some people were still fasting and he said: 'Those are the disobedient ones.

"The Messenger of Allah used to fast until we said: 'He will not break his fast.' And he used not to fast until we said: 'He will not fast.' And I never saw the Messenger of Allah fast more in any month than in Shaban."

"The Messenger of Allah used to fast (all of) Shaban except a little."