"build their treasures in Heaven"....

" You can't change all that is wrong in this great big world,but you can have an impact, even if it is just a tiny,positive impact on a stranger that receives a smile from you on the street today. There's so much we can do for others, and in the end, what we do for others ends up benefiting us tenfold. So let's do this. Let's make our little worlds amazing today "

Here is always a consequential effect on every action irrespective of you mentioning it or not. It could be good or bad. Why do you think people do charity? Its the sort of fulfilment you get by helping people. Going by your logic then that too is a selfish act.
First take notion of god out of equation. Tell those fairy tales to kids and i will only accept logical and proven explanations. I believe in science. :))