If you are a responsible gambler and moreover a professional gambler, why should stop or quit gambling for a month to give the allocated money to them?
Why we don't change our mind to:
I think if you are a professional gambler or if you are not addicted to gambling, leaving gambling for just one month because you want to help shouldn't be a problem.
"Doing gambling and try to win gambling, then use the profits to give the poor in a certain amount".
So, your plan to help the poor still can happen and you can still do gambling activities during that month.
If you are having this kind of mindset then you are not really ready to help, I once said it before, their is no assurance that you are going to win whenever you are gambling, what if the month is not really a good month for you, what if you are not lucky that month and you endup losing the money you allocated for gambling for the month, then you won't help them.