and it appears that his guardian must give it in charity on his behalf, exactly as with zakah. Zakah is due from an insane person and from a minor.

If he says, “If Allah cures my sick person, then I vow to Allah that I will fast,” and the sick person recovers while the one making the vow is insane, this is the point of difficulty in reality.

This requires further consideration. Should we say that, since this man made fasting binding upon himself while he was of sound mind, it must be discharged on his behalf? Or should it be said that it became binding upon him at a time when he was not among those capable of fasting? This differs from financial obligations, for an insane person is liable for financial dues when the conditions for liability are met, such as zakah, compensation for property that he damages, and the like.

Issues:

First: Must a vow be fulfilled immediately? And does the hadith, “There is no vow involving disobedience,” imply that making vows is permissible, despite the authentic prohibition of them?

If it is linked to a condition, it must be fulfilled immediately: from the moment the condition occurs, fulfilling it becomes obligatory. If it is unconditional, there is a difference of opinion; the correct view is that it must be fulfilled immediately.

The hadith either indicates that such a vow is validly contracted, or its meaning is that no vow involving disobedience is to be fulfilled.

Second: Is there any difference between an oath and a vow?

Yes, there is a difference between them. If someone vows to pray two rak'ahs, he must pray two rak'ahs. But if he swears an oath that he will pray two rak'ahs, it is not obligatory for him to do so, though it is recommended that he do so.