that are authentic. Imam Ahmad ibn Hanbal, may Allah Most High have mercy on him, said, “The hadith concerning them has been authentically transmitted through ten routes.” Muslim included these in his Sahīh, and al-Bukhārī included some of them.

These three kinds of worship are prescribed; the question that remains, however, concerns the prescribed extent of each. It was on this subject that the Book of Moderation in Worship was written. Ubayy ibn Kaʿb and others said:

“Moderation in following the Sunnah is better than strenuous devotion to innovation.”

The question concerning fasting continuously, fasting throughout the year except for the two Eid days and the days of Tashrīq, and spending the entire night in prayer is whether this is recommended—as a group of jurists, Sufis, and devout worshippers have held—or disliked, as the Sunnah indicates, even if permissible. Yet fasting on alternate days is better, and praying for a third of the night is better. A detailed discussion of this belongs elsewhere.

The purpose here is to discuss kinds of worship that are not prescribed and that arose among later generations, such as retreats in seclusion, which resemble the prescribed retreat in the mosque. The prescribed retreat in mosques, as practised by the Prophet, may Allah bless him and grant him peace, and his Companions, is indeed one of the prescribed acts of worship. As for retreats in seclusion, some cite his devotional worship in the Cave of Hirā’ before revelation as evidence for them, but this is a mistake;