unless the intention has been formed during the night, whether the fast is obligatory or voluntary. This is based on the apparent meaning of the hadith of Hafsa and Ibn Umar, which is transmitted both as traced back to the Prophet and as a statement of a Companion: “There is no valid fast for one who did not form the intention to fast during the night.”

According to the third view, an obligatory fast is valid only if the intention is formed during the night, as indicated by the hadith of Hafsa and Ibn Umar. This is because the entire period must be spent fasting, and an intention cannot apply retroactively. A voluntary fast, however, is valid with an intention formed during the day, as indicated by his words, “Then I am fasting.” Similarly, prescribed prayer requires certain pillars—such as standing and being firmly positioned on the ground—that voluntary prayer does not require. This is a dispensation granted by Allah to His servants concerning the ways in which they may perform voluntary acts of worship. Indeed, the forms of voluntary worship are always broader than those of obligatory worship. As for their fasting on the day of Ashūrā, if it was obligatory, it only became obligatory for them during the day because they had not known of the obligation beforehand. The claim reported by some later writers on juristic disagreement that this occurred during Ramadan is false and has no basis.

This is the most balanced of the views, and it is the position of al-Shāfiī and Ahmad. Differing views are reported from both of them as to whether a voluntary fast is valid with an intention formed after the sun has passed its zenith. The more evident view is that it is valid, as has been reported from the Companions.

Their followers also differed concerning the reward: is it the reward of an entire day, or does it begin only from the time the intention was formed? The position explicitly stated by Ahmad is that the reward begins from the time of the intention.

They likewise differed over whether the intention must specify the particular fast. On this issue, there are three views in Ahmad’s school and elsewhere: