The most fundamental question to ask in anything that has got to do with Jesu's doctrine is the faith in him that does not come by the deeds of the law in any regard and only goes on to show that you God's no matter whether you are saved or not........ Sounds heretical?
Well if you are not saved you were made by Him and going to be judged by His standards......
The only law that the Christian is expected to keep is the law of liberty which does not involve the kind of tithing teaching according to Hebrew tradition.
If you were to go by the words of Jesus literarily in Mathew 23:23-25, you would know he doesn't place any form of premium on this concept and to him it is regarded persona non-gratis. I would rather that you know God is not worshipped by the hands of men and he regards your help of love to your neighbour than to tithe your everything.