al-Hasan bin 'Ali al-Halwani الحسن بن علي الخلال الحلواني · Fasting (Kitab Al-Siyam)

The Prophet (ﷺ) said: Do not fast (for Ramadan) before the coming of the month until you sight the moon or complete the number (of thirty days); then fast until you sight the moon or complete the number (of thirty days).

A man came to the Prophet (ﷺ) and said: I am undone. He asked him: What has happened to you ? He said: I had intercourse with my wife in Ramadan (while I was fasting). He asked: Can you set a slave free ? He said: No. He again asked: Can you fast for two consecutive months ? He said: No. He asked: Can you provide food for sixty poor people ? He said: No. He said: Sit down. Then…

Eat. He said: I am fasting. 'Amr said: Eat, these are the days on which the Messenger of Allah (ﷺ) used to command us to break fast, and forbid us to keep fast. The narrator Malik said: These are the day of al-tashriq (i.e. 11th, 12th, and 13th of Dhu al-Hijjah).

He said: Messenger of Allah, tell me about keeping fast on Monday and Thursday. He said: On it I was born, and on it the Qur'an was first revealed to me.

Some food was presented to me and Hafsah. We were fasting, but broke our fast. Then the Messenger of Allah (ﷺ) entered upon us. We said to him: A gift was presented to us; we coveted it and we broke our fast. The Messenger of Allah (ﷺ) said: There is no harm to you; keep a fast another day in lieu of it.