3- The Prophet ﷺ measured acts of worship by the doer’s capacity. He first restricted ʿAbd Allah to fasting three days of every month; when ʿAbd Allah asked for more and the Prophet ﷺ perceived both eagerness and ability in him, he said, “Then fast one day and break the fast for two.” When ʿAbd Allah still sought a further increase, he guided him to the best form of fasting, saying, “Then fast one day and break the next.”
4- The upper limit of virtuous fasting is to fast one day and eat the next—the fast of David, peace be upon him.
5- Perpetual fasting is discouraged, for it opposes the Prophet’s ﷺ instruction, “Fast and break the fast,” and the hadith, “He has not truly fasted who fasts forever.” (1)
6- The tolerance of this sharia is evident in its disapproval of excess and affectation and its call for ease and facilitation, for that is more energizing and more conducive to perseverance.
Hadith Three
ʿAbd Allah ibn ʿAmr ibn al-ʿĀṣ—may Allah be pleased with him—reported that the Messenger of Allah ﷺ said:
“The most beloved fast to Allah is the fast of David, and the most beloved prayer to Allah is the prayer of David. He would sleep half the night, stand for one-third of it, and then sleep the final sixth; and he would fast one day and eat the next.”
General meaning
We have already spoken of the mercy and ease of this dispensation. The One who created humans and jinn for His worship loves that they serve Him in a way that is manageable, free of hardship and strain. Hence the fast and prayer He loves most are those practiced by the prophet David, peace be upon him: he would fast on alternate days, and during the night he would sleep the first half so that he might rise refreshed and light for worship, pray for one-third of it, and then sleep the last sixth so as to begin the day vigorous for its acts of devotion. This is the pattern the wise Lawgiver commended.
Points derived from the ḥadith
1- Fasting one day and eating the next is the finest of all forms of fasting, even superior to fasting every day of the year.
2- The optimal regimen for night worship is to sleep the first half of the night, stand in prayer for the next third, and then sleep the final sixth. This allows the body its needed rest at the outset, permits worship during the hour of divine descent, and concludes with a brief rest that leaves one lively for the dawn prayer and its remembrances.