As for Sunday, some scholars hold that it is recommended for a person to fast it, while others consider it disliked.

Those who recommend it say: it is a festival day for the Christians, and a festival is a day of eating, delight, and joy; therefore, differing from them is preferable, and fasting this day constitutes a departure from their practice.

Those who consider fasting it disliked say: fasting is a form of venerating a time, and since Sunday is a festival day for the disbelievers, fasting it constitutes a form of veneration for it. It is not permissible to venerate that which the disbelievers venerate as one of their religious rites.

In summary, fasting on Tuesday and Wednesday is permissible: singling either of them out is neither sunnah nor disliked. Singling out Friday, Saturday, or Sunday is disliked, though singling out Friday is more strongly disliked, since the hadiths prohibiting this are established without dispute. However, joining them to the day after them is unobjectionable. As for Monday and Thursday, fasting them is sunnah.

And six days of Shawwal, …

His statement, “and six days of Shawwal,” means: It is sunnah to fast six days of Shawwal, due to the Prophet’s saying, peace and blessings be upon him: “Whoever fasts Ramadan and follows it with six days of Shawwal, it is as though he has fasted the entire lifetime.” (1) Thus, it is sunnah for a person to fast six days of Shawwal.

Point of benefit: The Prophet’s words, peace and blessings be upon him, “and follows it with six days of Shawwal”—it is known that using the masculine form of a number indicates that the thing counted is feminine. Yet what is fasted is the day, not the night; so why did he not say “six” using the feminine form?

The answer is that the rule concerning a number’s being masculine with a feminine noun