There are multiple points here. One that argues that a moral action is only just depending on intent. I can make a reasonable argument based on psychological theory that this line of reasoning presents its own problems. Brain scans indicate that when helping others pleasure portions of the brain are lit up - same thing happens when someone smiles at you or thanks you. Thus I can make an argument that it is psychological impossible to help someone without gaining something yourself.
if you seriously believe, that you are listening to, and talking to, and doing god's will - nothing should stop you. your family, your friends, the laws .... if you sincerely believe that you are doing the express will of the creator of the universe - that is an inherently dangerous idea.
so your argument could be "well, what if that idea is to justify and drive people to help each other"
well great, except helping each other does not need supernatural justification. you can see the results directly.
this can accuracy be summed up by the idea that good people will do good with or without religious justification, but for good people to do evil: it takes religion.