A “vow of devotion” is, for example, when the person making the vow wishes the condition to be fulfilled and undertakes to perform the consequent act out of gratitude to Allah Most High. He might say: “If Allah heals my sick relative, I undertake to fast for such-and-such a period, or give such-and-such in charity,” or something similar. He must fulfil this vow, as the Prophet, may Allah bless him and grant him peace, said:

“Whoever vows to obey Allah, let him obey Him; and whoever vows to disobey Allah, let him not disobey Him.”

Narrated by al-Bukhārī.

As for a “vow of obstinacy and anger,” the person making it intends neither the condition nor its consequence to occur. For example, someone tells him, “Travel with so-and-so,” and he replies: “If I travel, I undertake to fast for such-and-such a period, or to perform Hajj.” His intention is to do neither the conditional act nor the consequent act.

This is like someone declaring himself a Jew or a Christian if he does such-and-such, or saying, “If I do such-and-such, I am an unbeliever,” and similar statements. The imams agree that if the condition is fulfilled, he does not thereby become an unbeliever. Rather, according to Abū Hanīfa and the well-known position reported from Ahmad, he must offer expiation for an oath. According to Mālik and al-Shāfiʿī, nothing is required of him.

This differs from saying: “If you give me the money, I will disbelieve.” He becomes an unbeliever by this statement; indeed, his disbelief takes effect immediately, because he intends to disbelieve when the condition is fulfilled.

A group of jurists considered the wording used by the person making the vow and said: “He has made the ruling conditional upon something, so it must take effect when that condition is fulfilled.” They did not distinguish between a “vow of obstinacy” and a “vow of devotion.”

The Companions, the majority of the early generations, and the scholars of discerning judgment, however, said: “What matters is the meaning of the words.” Here, the person laying down the condition intends both the condition and its consequence to occur, whereas in the other case he intends to avoid