Now that these categories have been established, our present issue belongs to the type in which a cause is explicitly mentioned in one instance and functions in another.

Specifically, the Prophet—may peace and blessings be upon him—forbade designating particular times for prayer or fasting, yet allowed such worship when one does not intentionally single out those times.

Muslim records in his Ṣaḥīḥ, on the authority of Abū Hurayrah (may Allah be pleased with him), that the Prophet said:

“Do not single out the night before Friday for night-vigil above other nights, and do not single out Friday for fasting above other days, unless it coincides with a fast one of you is already observing.”

In both Ṣaḥīḥs it is likewise reported from Abū Hurayrah that he heard the Prophet say:

“None of you is to fast on Friday unless he fasts a day before it or a day after it.” (This wording is from al-Bukhārī.)

Al-Bukhārī also narrates from Juwairiyah bint al-Ḥārith (may Allah be pleased with her):

“The Prophet entered upon her on a Friday while she was fasting and said, ‘Did you fast yesterday?’ She replied, ‘No.’ He said, ‘Do you intend to fast tomorrow?’ She replied, ‘No.’ He said, ‘Then break your fast.’ ”

And in the two Ṣaḥīḥs, Muḥammad ibn ʿAbbād ibn Jaʿfar related: “I asked Jābir ibn …”