Schaar mitzvah mitzvah.
A Jewish concept that the reward for a good deed is the chance to do another.
Judaism teaches that we are meant to fulfill the commandments (or mitzvot in Hebrew) and will be rewarded and punished accordingly for our actions. With that said there is the belief that all the joys of heaven are nothing compared to the chance to do a mitzvah. For that reason there is a common tradition in cemeteries for Jewish men to hide their tzitzit (a cloth worn by Jewish men under their clothes that has a few strings hanging out) as not to make the dead jealous for their inability to do mitzvot.
I heard a story once of a Rabbi whose life was saved by modern medicine but lost the ability to eat normally and had to be fed intravenously. When his students told him the news and he began to cry, they were puzzled. He explained that he was upset because he had lost the ability to say a blessing over his food. All joy stems from God, thus there is no joy like the ability to do a mitzvah so in turn, there is no greater reward for doing one then getting to do another. | 
