It is recommended to fast the White Days …

His statement, “It is recommended to fast the White Days”: Had the author used a more general wording and said, “It is recommended to fast three days of every month, and it is preferable that they be the White Days,” that would have been better.

His statement, “It is recommended”: In the terminology of the scholars of legal theory, a recommended act is one for whose performance, in compliance with the command, a person is rewarded, while one who leaves it is not punished. Recommended acts have levels and ranks in terms of superiority and the abundance of their reward, just as obligatory acts do. Yet obligatory acts are more beloved to Allah, Most High, as is established in the authentic hadith qudsi, in which Allah says: “My servant does not draw nearer to Me with anything more beloved to Me than that which I have made obligatory upon him.” (1)

His statement, “the White Days”: These are the thirteenth, fourteenth, and fifteenth days of the lunar month. The evidence that fasting them is recommended is that the Prophet, peace and blessings be upon him, instructed that they be fasted. (2)

They are called the White Days because their nights are illuminated by the light of the moon. Thus, they are called the White Days—that is, the days of the white nights. The description, in fact, applies to the nights, since they become white through the moonlight. Medical scholars have mentioned that there is also a physical benefit in fasting these three days, because this is a time when the blood is said to surge and increase; for, by Allah’s permission, the blood is connected to the moon. When one fasts, the pressure caused by the abundance of blood is alleviated. This is a medical benefit, but—as we have often said—physical benefits should be given secondary consideration in relation to acts of worship, so that a person may be worshipping Allah