What is the ruling on one who vowed to pray four additional rak'ahs if he is late for the obligatory prayer, and is it permissible for him to pray them quickly or to change the manner of their performance, and what if his intention changed so that he began to pray out of fear of these rak'ahs, not out of love for prayer?

If the vow is a vow of obstinacy and anger (nadhru lajaj wa ghadab), which is intended to urge the doing or refraining from something, not an act of closeness to Allah, then, according to the preponderant opinion, it is not obligatory to fulfill it. Rather, the person who made the vow has the choice between fulfilling it or offering expiation (kaffarah).

If you believe that it is better for your heart not to be bound by it, then you may release yourself from it by offering expiation. If you believe it is better to adhere to it, then we advise you to have humility in prayer and to remember its status and the importance of humility.

One must hasten to perform good deeds, such as praying at the beginning of its prescribed time, as it is among the most beloved deeds to Allah, while being careful not to delay prayer beyond its time to avoid the severe warning against those who are negligent with it.