Abu Hurairah · The Book of Vows

Do not take vows, for a vow has no effect against Fate; it is only from the miserly that something is extracted.

It does not avert Fate, but is the means by which something is extracted from the miser.

The vow does not bring anything near to the son of Adam which Allah has not ordained for him, but (at times) the vow coincides with Destiny, and this is how something is extracted from the miserly person, which that miser was not willing to give.

Allah's Apostle (ﷺ) found an old man walking between his two sons supported by them, whereupon Allah's Apostle (ﷺ) said: What is the matter with him? He (the narrator) said: Allah's Messenger, they are his sons and there is upon him the (fulfilment) of the vow, whereupon Allah's Apostle (ﷺ) said: Ride, old man, for Allah is not in need of you and your vow.