There is no “reward”, and to look for it is to take one’s sight away from the truer goal of self fulfillment. There is, however, an earning of grace (for lack of a better word) that guides one to be aware of where the stepping stones are in order to cross the rivers of life safely. And, at some point near the end of the life-long journey, one can turn to look back and see the long distances that have been traveled and the great strides that have been made.
By living in synchronicity with the workings of the Universe, and one’s particular place and time within it, one contributes to the Whole and also receives what is needed from the Whole. To give in order to receive, or to do the work with the expectation of reward, is to coat the gift/ work in one’s own purpose, thereby preventing the full purpose of the Universe from fulfilling Itself through oneself.