Know that fasting is among the finest righteous deeds. It is established in a hadith qudsi that Allah, exalted is He, says: “Every deed of the son of Adam is for him except fasting; it is for Me, and I shall reward for it.” (1) The reward for acts of worship is multiplied from tenfold up to seven hundredfold, and then many times more. Fasting, however, is an exception: Allah Himself will reward for it. This means that its reward is exceedingly great.

The scholars have said that this is because fasting combines the three kinds of patience: patience in obeying Allah, patience in abstaining from disobeying Allah, and patience in bearing His decrees. It is patience in obeying Allah because a person endures in performing this act of worship. It is patience in abstaining from disobedience because he avoids what is forbidden to the fasting person. And it is patience in bearing Allah’s decrees because the fasting person experiences the discomfort of thirst, hunger, lethargy, and physical weakness. For this reason, fasting is among the highest forms of patience, since it combines all three types. Allah, Most High, says: “Indeed, the patient will be given their reward without account.” [al-Zumar: 10]

The author then mentions voluntary fasting in general terms, without detail. In reality, however, it is divided into two categories: unrestricted voluntary fasting and specified voluntary fasting.

Specified voluntary fasting is more strongly recommended than unrestricted voluntary fasting, just as with prayer: specified voluntary prayers are superior to unrestricted voluntary prayers.