– Then He provided a further concession, declaring: “Whoever among you is ill or on a journey shall fast the same number of days at another time” [Qur’an 2:184]. Because fasting is ordinarily burdensome in such situations, Allah permitted both the sick person and the traveller to break the fast. Yet, since the servant must still reap the benefit intended by fasting, He commanded them to make up the missed days once the illness is gone, the journey has ended, and ease has returned.
The phrase “the same number of days at another time” indicates that one must make up exactly the number of days missed from Ramadan, whether the month was complete or incomplete. It also shows that one may replace long, hot days with short, cool ones, and vice versa.
On that basis we answered a question put to us: some Muslims live in regions where, at certain times of the year, the night lasts only about four hours—or even less—and that period may coincide with Ramadan. If they cannot complete so demanding a fast, are they allowed simply to feed the poor instead?
Our reply was that whoever is unable to fast under those conditions should postpone the fast to another time when the days are shorter and he is able to perform it, just as Allah instructed the sick person to do—and this case is even more deserving of that ruling. As for anyone who is able to fast during those long days, it remains obligatory for him; a healthy resident may not delay it. This is the substance of the answer.
– Concerning His words: “For those who can bear it, a ransom is to feed a poor person” [Qur’an 2:184]:
It has been said that this verse applied at the very beginning, when fasting was first enjoined. Since the people were unaccustomed to the practice and the new obligation was hard for them, the All-Wise Lord introduced it in the easiest manner: anyone capable of fasting had a choice—either to fast, which is the better and more complete option, or to pay the ransom of feeding a poor person, which would suffice. Later, once they had become used to fasting and it had become essential for those who were able, He made it compulsory for them without that choice.