Waki' bin al-Jarrah وكيع بن الجراح · Fasting (Kitab Al-Siyam)

The Prophet (ﷺ) said: When any of you hears the summons to prayer while he has a vessel in his hand, he should not lay it down till he fulfils his need.

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).

Hunaydah ibn Khalid narrated from his wife on the authority of one of the wives of the Prophet (ﷺ) who said: The Messenger of Allah (ﷺ) used to fast the first nine days of Dhul-Hijjah, Ashura' and three days of every month, that is, the first Monday (of the month) and Thursday.

The Messenger of Allah (ﷺ) said: He who does not determine to fast before dawn does not fast.