Can a traveler fast during Ramadan on behalf of another obligation, such as a vow or missed fast (Qada)?
General Chapter
Al-Mughni
Book of Fasting
Primary text
A traveler in Ramadan is not permitted to fast on behalf of another obligation, such as a vow (Nadhr) or a missed obligatory fast (Qada). This is because the permission to break the fast was granted as a concession and lightening (rukhsah and takhfif) for the traveler. If the traveler does not intend this concession for themselves, they must fulfill the original obligation. If a traveler intends to fast a specific day that is not Ramadan, the fast is invalid, neither counting for Ramadan nor for what they intended.
Supporting text
Abu Hanifa held that if the traveler intends a different obligatory fast, the fast counts for what was intended. His reasoning is that the time allows for breaking the fast, therefore it is permissible to fast it for an existing obligation, similar to fasting obligations outside of Ramadan. This opinion is supported by the majority of scholars according to the text.