What is the ruling if one vows to fast a continuous month but breaks the fast without a valid excuse?
General Chapter
Al-Mughni
Book of Vows
Primary text
If one vows to fast a specific continuous period (other than a specified month) and breaks the fast without a valid excuse, they must restart the fast and no expiation is due. This is because leaving the vowed continuous fast without excuse, while capable of fulfilling it, necessitates performance, similar to one who fasts before performing a specified vow.
Supporting text
If the fast is broken due to an excuse such as menses or illness, the person has two options: either restarting the fast with no penalty, as the vow was fulfilled in its proper manner, or continuing from where they left off and offering the expiation of an oath. Expiation is incumbent due to leaving the vowed act even if unable, supported by the Prophet's instruction to the sister of Uqba ibn Amir regarding expiation for inability to walk, and because the vow resembles an oath. Continuity is permitted for an excused break because an excused break does not sever continuity in ruling, evidenced by the ruling on two consecutive months of fasting.