Is the prohibition of fasting on Saturday an absolute prohibition, with no exception made for it save for a prescribed duty? And is the fasting of David (peace be upon him) to be understood as having been permissible for them and not for us? And will one who abstains from fasting on the Day of Arafah if it falls on a Saturday, out of obedience to God, be rewarded for that?

Fasting on Saturday is permissible if another day is added to it. It has been reported that the Prophet, peace and blessings be upon him, used to fast on Saturdays and Sundays. The majority of scholars interpreted the prohibition of singling out Saturday for fasting as merely disliked (makruh), not forbidden (haram), except for what Allah has obligated, or what coincides with a confirmed Sunnah like Arafah and Ashura, or if it was part of the fast of David.