A vow cannot deflect anything of Allah’s decree. Yet, should the fulfilment of a vow happen to coincide with the attainment of the desired outcome or the removal of some hardship, the person may imagine that this result came about because of the very vow he had made conditional upon that benefit or that relief.

By default the Muslim enjoys ample latitude, but when he vows an act of worship he imposes on himself what Allah has not made obligatory. Should he then fall short in performing it, he becomes liable to sin.

Allah has apportioned the obligatory duties to His servants in a measure that they can easily discharge, and He has left whatever is beyond that as voluntary, lest worship become burdensome. This is a broad principle: whoever reflects upon it realises that when a servant thrusts himself into what Allah has not required of him, he exposes himself to the risk of non-fulfilment, and that only a few actually live up to what they bind themselves to, owing to the soul’s shortcomings and Satan’s discouragement. Allah alluded to this small minority when He said, “Among the believers are men who have been true to what they pledged to Allah” (Al-Ahzab 33:23).

The subject of vows is one of the remarkable issues of the law: initiating a vow is disliked, yet fulfilling it is obligatory. Normally, the legal means share the ruling of their ends, but the wisdom behind the exception here is clear.

The vow that is merely disliked is the one made for an act of obedience to Allah. As for vows made to the dead, to graves, to false deities, to devils, and the like, that constitutes outright shirk (associating partners with Allah). We seek refuge in Allah from His wrath and from the causes that incur it.

Shaykh al-Islam said: “When something already obligatory in the Sacred Law is then the subject of a servant’s vow, or a covenant, or a pledge administered by the imam, its obligation now rests on two grounds. Neglecting it thus entails abandoning what is obligatory by the Law and what is obligatory by the vow; consequently, the one who abandons it deserves the punishment due both to one who violates covenants and treaties and to one who disobeys Allah and His Messenger. This is the verified position, explicitly stated by Ahmad and affirmed by a number of scholars.”