However, the majority of scholars held that a vow to commit a sin entails no expiation, though fulfilling it is forbidden. They cited as evidence the hadith of Aisha, may Allah be pleased with her, to which we referred earlier: the Messenger of Allah, peace and blessings be upon him, said: “Whoever vows to disobey Allah must not disobey Him.” But we say: since an authentic hadith has been reported containing an additional wording, it must be accepted—namely, the expiation for an oath.

Reason also supports this, for this man made a vow but did not fulfill it. We maintain that his vow became binding, since he imposed it upon himself; yet he cannot fulfill it, because it entails disobedience. Thus, he has made a vow that he did not fulfill, and expiation is therefore due from him. This is like one who swears to commit a sin: we tell him, “Do not do it, but you must offer the expiation for an oath.” Thus, the view held by Imam Ahmad, may Allah have mercy on him—though it is one of his distinctive positions—is closer to what is correct: he must not commit the sin, and he must offer the expiation for an oath.

If, then, someone vows to fast on a day on which fasting is prohibited, must he make up that day and offer expiation because its appointed time has passed, or need he not make it up? The apparent meaning of the hadith is that he need not make it up and that only expiation is due. Thus, if he says, “By Allah, I shall fast on the day of Eid,” and we tell him, “You may not fast,” is he required—as held in the school—to fast another day in its place along with offering expiation, or is he not required to do so? The apparent import of the text is that he is not required, because the original specification was forbidden and sinful.

The jurists, may Allah have mercy on them, distinguish between the two, saying: if the prohibition is due to a factor connected to the person himself, no make-up is required; but if it is due to a factor connected to the time or place, he must make it up.