He promised his mother to give her money that she could put towards building a mosque, then she died

My mother asked me for some money that she could put towards a mosque that was being built in our village, but at that time I did not have any money that was surplus to my needs with which I could fulfil her request. So I promised her that in the future I would give her money if Allaah willed. Then I travelled outside of my country to seek halaal provision. During that period, Allaah decreed that my mother fell sick and she died as a result. Does that promise that I made to her remain as a debt that I owe, and do I have to give what I promised her to that particular mosque, or is it permissible to give it to another mosque that needs money, or is that promise no longer a debt that I owe and am I thus pardoned from it?.

Praise be to Allaah.

Yes, you must certainly fulfil your promise and give that money to the mosque that your mother wanted to give it to, as that you promised to do. It is part of honouring her and treating her kindly to fulfil this promise, in the hope that Allaah, may He be glorified and exalted, will accept its and benefit her thereby. This is part of honouring her and treating her kindly. If the mosque that your mother wanted to support has no need of it and its expenses are covered, then you may give it to any other mosque, but as we have mentioned, you should not neglect this promise and fail to give this money, rather you should and most certainly must fulfil this promise, as a way of honouring your mother. And Allaah knows best. End quote.