What is the ruling on fulfilling a vow to perform a thousand rak'ahs of prayer, fast for ten days, and give 1500 dinars in charity to ward off an affliction from one's mother, knowing that the mother refuses to give 1000 dinars of it in charity, and is fasting three days sufficient as expiation for that, and is this vow valid in the first place?

The contingent vow (nadhr (definition) mu'allaq) is disliked, and the Prophet, peace and blessings be upon him, forbade it because it does not avert anything; rather, it merely extracts from the miserly. However, whoever vows an act of obedience to Allah must fulfill it, based on the Prophet's saying, peace and blessings be upon him: "Whoever vows to obey Allah, let him obey Him." Therefore, this vow must be fulfilled if the condition upon which it was made is met. It is not permissible to substitute the vow with something else, or to expiate for it with fasting or anything else, unless you are permanently incapable of fulfilling it, in which case you must offer an expiation for breaking an oath (kaffarat yamin (definition)). If the inability is to fast, then in addition to the expiation, you must feed one poor person for each day. As for the money your mother gave for Umrah (definition), it is not part of the vow; rather, it must be spent on what your mother specified, because the condition of the giver is legally binding, based on the Prophet's saying, peace and blessings be upon him: "Muslims are bound by their conditions."