Question: Some people dedicate the month of Rajab to fasting. Has anything authentic been established on this point?
Answer: No specific act of worship has been soundly reported for the month of Rajab—no fast, no prayer, no ʿumrah, nothing at all that is peculiar to it. Those who single it out with special devotions are innovators, for they have introduced into the religion what does not belong to it. Neither Allah nor His Messenger prescribed any particular act of worship in Rajab: no ʿumrah, no sacrifice, no special night vigil, and no fast on set days. Rajab is just like any other month.
Muḥarram, to be sure, is venerated because it is one of the four sacred months, but to reserve exclusive acts of worship for it to the exclusion of other times is likewise an innovation.
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Fasting the White Days
Question: In Ibn al-Qayyim al-Jawziyyah’s book Zād al-Maʿād I read that the Messenger ﷺ used to fast the white days—the thirteenth, fourteenth, and fifteenth of every month—while travelling and while resident. Elsewhere I found that fasting is forbidden on the days of Tashrīq, the last of which is the thirteenth. How can these two statements be reconciled?
Answer: The Prophet ﷺ encouraged fasting three days of every month, whether they fall at the beginning, the middle, or the end. The most virtuous choice, however, is for them to be the white days: the thirteenth, fourteenth, and fifteenth. This is what is preferable; but if a person fasts the three days on other dates within the month, there is no harm in that. He has fulfilled the prescribed Sunnah and, Allah willing, will receive the reward.