It was narrated from Abu Mujibah Al-Bahili that his father or, his paternal uncle, said: “I came to the Prophet (ﷺ) and said: ‘O Prophet of Allah, I am the man who came to you last year.’ He said: ‘Why do I see your body so thin (and weak)?’ He said: ‘O Messenger of Allah! I do not eat during the day; I only eat at night.’ He said: ‘Who commanded you to punish yourself?’ I said: ‘O Messenger of Allah! I am strong enough.’ He said: ‘Fast the month of patience* and one day after it.’ I said: ‘I am strong enough (to do more).’ He said: ‘Fast the month of patience and two days after it.’ I said: ‘I am strong enough (to do more).’ He said: ‘Fast the month of patience and three days after it, and fast the sacred months.’”

It was narrated that Abu Hurairah said: “A man came to the Prophet (ﷺ) and said: ‘Which fasting is better after the month of Ramadan?’ He said: ‘The month of Allah which is called Muharram.’”

It was narrated from Ibn ‘Abbas that: The Prophet (ﷺ) forbade fasting Rajab.

It was narrated from Muhammad bin Ibrahim that Usamah bin Zaid used to fast the sacred months. The Messenger of Allah (ﷺ) said to him: “Fast Shawwal.” So he forsook the sacred months and he continued to fast Shawwal until he died.