Those that are on the receiving end are not under any obligation, other than a moral one
But that's the point. To pay first, you are operating under faith that this is the right thing to do. To pay back after you have received is more like settling a moral debt. For some people taking that leap of faith- doing good before being guaranteed that there is something in it for them- is really hard. They have what I consider to be a narrow and limited view of their self-interest, and don't believe or understand that making the world better is in their self interest, if not obviously and directly so.
But that's the point. To pay first, you are operating under faith that this is the right thing to do. To pay back after you have received is more like settling a moral debt. For some people taking that leap of faith- doing good before being guaranteed that there is something in it for them- is really hard. They have what I consider to be a narrow and limited view of their self-interest, and don't believe or understand that making the world better is in their self interest, if not obviously and directly so.