Is it permissible to fast on the days of Sunnah (Mondays, Thursdays, the Ayyam al-Bid [the white days], and Rajab) if they coincide with days of not fasting in the fast of David? And is it possible to fast the days after the first day of Eid al-Fitr and Eid al-Adha? And are the days on which fasting is prohibited excluded from the fast of David? And is it obligatory to renew the intention for the fast of David every night with the aforementioned intentions, or is a comprehensive intention at the beginning sufficient?

Fasting of David, peace be upon him, is a great act of worship and among the best forms of fasting. If Eid al-Fitr falls on a Thursday or a Monday, fasting on those days is preferable. However, if it coincides with the first of Rajab or the beginning of a lunar month, then it is better to adhere to the fast of David, as well as in the months of Muharram and Rajab.

It is forbidden to fast on the day of Eid al-Fitr, Eid al-Adha, and the days of Tashreeq, and such fasting is invalid. The six days of Shawwal can be intended alongside the fast of David. The intention does not need to be renewed for every fast; it is sufficient to intend it at the beginning of each day of fasting. Intending for future fasts when fasting on the first day is not sufficient.