Milhan in which the Prophet ﷺ said, “It is like fasting for a lifetime.” Accordingly, whoever makes a habit of fasting those three days each month is regarded as though he has fasted for his entire life.
-
The best days to observe this fast are the thirteenth, fourteenth, and fifteenth of the lunar month, as indicated by the present hadith and by what al-Nasaʾi narrated with a sound chain from Jabir: the Prophet ﷺ said, “Fasting three days of every month is like fasting for a lifetime, and the white days (ayyam al-bid) are the mornings of the thirteenth, fourteenth, and fifteenth.”
-
The recommendation to fast the three white days is the view held by the overwhelming majority of scholars; indeed, al-Wazir reports a consensus on their virtue.
-
The exclusive merit assigned by the purified Sunnah to fasting on these three white days also contains a scientific marvel: physicians state that bodily moisture increases as the moon’s light grows and reaches fullness, while fasting helps reduce these excess fluids and purge them from the body. When a person fasts while his body is replete with such moisture, the strain of fasting is lessened and becomes easier to endure. Truly, Allah’s law is replete with wisdom and hidden benefits.