Answer: He should make them up, and he will be granted their reward, just as an obligatory act is made up when it is delayed beyond its time due to an excuse, and just as a regular sunnah prayer is made up when it is delayed due to an excuse until its time has passed; this is established by the sunnah.
Note: Some scholars considered it disliked to fast the six days every year, out of fear that ordinary people might think fasting them is obligatory. This is a weak and unsound basis, for if it were accepted, it would necessitate deeming it disliked to perform the regular sunnah prayers connected to the obligatory prayers every day. But this consequence is invalid, and the invalidity of a necessary consequence demonstrates the invalidity of that which entails it. Moreover, the concern that is feared is dispelled through clarification.
And the month of Muharram, …
His statement, “And the month of Muharram,” means that it is recommended to fast the month of Muharram. It is the month that follows Dhu al-Hijjah, and it was made the first month of the year by the Rightly Guided Caliph, the Commander of the Faithful, Umar ibn al-Khattab, may Allah be pleased with him. Fasting in it is the best fasting after Ramadan, as the Prophet, peace and blessings be upon him, said: “The best fasting after Ramadan is Allah’s month of Muharram.” (1)
The scholars, may Allah have mercy on them, differed over which is more virtuous: fasting the month of Muharram or fasting the month of Sha‘ban.
Some scholars held that Sha‘ban is better, because the Prophet, peace and blessings be upon him, used to fast it except for a small portion of it, whereas no report has been preserved that he used to fast the month of Muharram. However, he encouraged fasting it by saying, “It is the best fasting after Ramadan.”
They also said: Fasting Sha‘ban holds the position of a regular sunnah prayer before an obligatory prayer, while fasting Muharram holds the position of unrestricted voluntary fasting; and the standing of a regular sunnah is superior to that of