And the third category comprises days whose singling out has been forbidden—such as Friday and the closing days of Shaʿbān.

If a person fasts these days together with others, the practice is not disliked; but once he isolates them for fasting it is prohibited, whether or not he intended that isolation and whether or not he deemed the fast superior.

It is clear that, had the harm of this act not lain specifically in isolating the day, the ruling would have been either a blanket prohibition—like the two ʿEids—or no prohibition at all, like the Day of ʿArafah and ʿĀshūrāʾ. That particular harm is absent from the other times; otherwise, forbidding the singling out would serve no purpose.

Thus it becomes evident that the mischief arises from assigning a special status to what has none, exactly as the Prophet’s wording—peace and blessings be upon him—indicates. The very act that is commanded or forbidden can itself contain the wisdom behind the command or prohibition, as in his statement, “Oppose the polytheists.”

Therefore, the wording that forbids dedicating a specific time to fasting or prayer shows that the corruption stems from that dedication itself. Since Friday is an honored day on which extra prayer, supplication, remembrance, Qur’an recitation, purification, fragrance, and respectable attire are recommended beyond other days, a person might assume that fasting on it is likewise preferable, and that spending its night in worship—just as fasting its day—has an advantage over other nights. To ward off this misconception, which arises only from singling the day out, the Prophet—peace and blessings be upon him—forbade doing so.