The Messenger of Allah (ﷺ) was asked about the observance of Saum (fasting) on the day of 'Arafah. He said, "It is an expiation for the sins of the preceding year and the current year."[Muslim].

The Messenger of Allah (ﷺ) observed Saum (fasting) on the day of 'Ashura' and commanded us to fast on this day.[Al-Bukhari and Muslim].

The Messenger of Allah (ﷺ) was asked about observing As-Saum (the fast) on the tenth day of Muharram, and he replied, "It is an expiation for the sins of the preceding year."[Muslim].

The Messenger of Allah (ﷺ) said, "If I remain alive till the next year, I shall also observe fast on the ninth of Muharram."[Muslim].

The Messenger of Allah (ﷺ) said, "He who observes As-Saum (the fasts) in the month of Ramadan, and also observes As-Saum for six days in the month of Shawwal, it is as if he has observed As-Saum for the whole year."[Muslim].

The Messenger of Allah (ﷺ) was asked about fasting on Mondays. He said, "That is the day on which I was born and the day on which I received Revelation."[Muslim].

The Messenger of Allah (ﷺ) said, "Deeds of people are presented (to Allah) on Mondays and Thursdays. So I like that my actions be presented while I am fasting."[At-Tirmidhi].

The Messenger of Allah (ﷺ) used to observe fast on Mondays and Thursdays.[At-Tirmidhi].

My friend (the Messenger of Allah) (ﷺ) directed me to observe fast for three days in every month, to perform two Rak'ah (optional) Duha prayer at forenoon and to perform the Witr prayer before going to bed.[Al-Bukhari and Muslim].

My friend (the Messenger of Allah) (ﷺ) directed me to observe Saum (fasting) for three days in every month, to perform two Rak'ah (optional) Duha prayer at forenoon, and to perform the Witr prayer before going to bed.[Al-Bukhari and Muslim].

The Messenger of Allah (ﷺ) said, "Observing Saum (fasting) on three days of every month is equivalent to a full month's fasting."[Al-Bukhari and Muslim].

I asked 'Aishah (May Allah be pleased with her). Did the Messenger of Allah (ﷺ) use to observe three days of Saum (fasting) in every month?" She replied, "Yes." I asked, "On which days in the month did he observed fast?" She replied that he did not mind on which days of the month he observed fast.[Muslim].

The Messenger of Allah (ﷺ) said, "If you want to observe Saum on three days in a month, then fast on the thirteenth, fourteenth and fifteenth of the (lunar) month."[At-Tirmidhi].

The Messenger of Allah (ﷺ) directed us to observe Saum (fasting) on the thirteenth, fourteenth and fifteenth of the (lunar) month.[Abu Dawud].

It was the practice of the Messenger of Allah (ﷺ) to not to omit fast on 'bright days' whether he was staying at a place or on a journey.[An-Nasa'i].

The Prophet (ﷺ) said, "He who provides a fasting person something with which to break his fast, will earn the same reward as the one who was observing the fast, without diminishing in any way the reward of the latter."[At-Tirmidhi].

Once the Prophet (ﷺ) visited us and I served him some food. He (ﷺ) asked me to eat. I replied that I was observing (optional) fast. He (ﷺ) said, "When people eat by a person observing fast, the angels keep asking Allah's forgiveness for that person until they have had their fill."[At-Tirmidhi].

The Prophet (ﷺ) came to visit Sa'd bin 'Ubadah (May Allah be pleased with him) who presented bread and olive oil to him. The Prophet (ﷺ) ate it and said, "The observers of fast have broken their fast with you (this is the literal translation, but the meaning is: 'May Allah reward you for providing a fasting people with food to break their fast'); the pious people have eat your food and the angels invoked blessings on you."[Abu Dawud].