ANSWER:

This is called a vow and it is mandatory to be fulfilled if what they asked for gets achieved. It is not recommended to make a vow to begin with. 

sheikh here are some people who keep the intention that if this work of mine is done by ALLAH I will give this much amount of charity and give only if that thing happens otherwise not even if they are suggested to do so they simply say my work for which I have to give it was not accomplished. Is this permissible.