Sayyiduna Usama bin Zaid (may Allah be pleased with him) says that the Messenger of Allah (peace and blessings be upon him) would fast so frequently and continuously that it would be said that now he will not leave any day without fasting. But then, when he would start leaving fasts, he would do so with such frequency that it would seem as if now he will not fast anymore, except for two days of the week. If those days happened to fall within his continuous fasting, then fine; otherwise, he would fast on those days among the days of not fasting. And the Messenger of Allah (peace and blessings be upon him) used to fast more in the month of Sha’ban than in other months. One day I said: O Messenger of Allah! Sometimes you begin to fast continuously in such a way that it seems you will not leave any day without fasting, but then you start leaving fasts in such a way that it seems you will not fast anymore, except for two days. If those days are included in your fasting, then fine; otherwise, you fast only on those days. He asked: Which two days? I said: Monday and Thursday. The Messenger of Allah (peace and blessings be upon him) said: On these days, the deeds of people are presented before the Lord of the worlds, and I wish that my deeds are presented before Allah while I am in a state of fasting. I said: I see that you fast more in Sha’ban than in other months? The Messenger of Allah (peace and blessings be upon him) said: This is a month between Rajab and Ramadan, which people are heedless of, although in it the deeds of people are presented before the Lord of the worlds, and I wish that my deeds are presented before Allah while I am in a state of fasting.

It is narrated from Mawla Usama that he was going with Sayyiduna Usama (may Allah be pleased with him) towards Wadi Qura in search of his wealth. He used to fast on Mondays and Thursdays. The servant said to him: Why do you fast on Mondays and Thursdays, when now you have become old and weak? He replied: The Messenger of Allah (peace and blessings be upon him) used to fast on these days. When he (peace and blessings be upon him) was asked about this, he (peace and blessings be upon him) said: On Mondays and Thursdays, the deeds of people are presented before Allah Almighty.

It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) used to fast frequently on Mondays and Thursdays. When he (peace and blessings be upon him) was asked about this, he (peace and blessings be upon him) said: The deeds of people are presented before Allah Almighty on Mondays and Thursdays, and Allah Almighty forgives every Muslim or every believer, except for two men between whom there is a severance of relations. Regarding them, Allah Almighty says: Defer their matter.

When Lady Aisha (may Allah be pleased with her) was asked about the fasts of the Messenger of Allah (peace and blessings be upon him), she said: He (peace and blessings be upon him) used to fast in the month of Sha'ban and would especially observe fasts on Mondays and Thursdays.