Musar su Salmi 108:3

And it is known that Chazal have said that one who fulfills a mitzvah, though we have been commanded to do so by the Blessed L-rd, is regarded by the Holy One Blessed be He as if he himself had originated it. And this is so with even an isolated mitzvah; how much more so with one which occupies such a great portion of the Torah. If one strengthens himself to fulfill them [(all the aspects of this mitzvah)], it will be accounted to him in time to come as if he himself had conceived of all these holy things that are written in these sections. How much greatness and honor he will be accorded in time to come because of this! And how much will his heart rejoice in this! In this man there will be fulfilled (Psalms 105:3): "The heart of the seekers of the L-rd will rejoice!"