As an example, sometimes I buy £10 worth of food to put in the food bank bin at the supermarket, but I wonder at my reasoning behind making the decision to do it.
Am I doing it because I want to 'get on Gods good side' and trying to balance out the scales of my deeds when they get stacked up at the end of my life? Like in medieval times when people would build an Abbey or something in order to set themselves up after they die.
Or is it purely selfish because I want to think of myself as a kind or good person, or I'm banking being good to offset for when I'm a crap person?
It's difficult to explain 
Does the instruction in the Bible saying you should give yourself over to the service of others and be charitable etc make any stipulation about the reasoning behind the acts?
It says to seek out places where you can help others, does it acknowledge that it's nigh on impossible for someone to do something purely for the act of selfless giving.
I know two people who are seemingly completely selfless and give to individuals and the community with relish, one is a committed Christian and the other isn't. Can they be doing it for similar reasons of self gratification (like the warm fuzzy feeling it gives you)? And does that matter if they're both helping support other people?
Can anyone tell me what exactly I'm trying to get at because I've not got a clue 
(I have a really strong faith and am loosely C of E but don't really go to services for reasons other than I don't like them)