If you will go in the way of My ordinances ... I will give your rain in the proper time (Leviticus 26:3-4).
Rashi explains that "going in the way of My ordinances" means that one will "toil in the Torah." This toil and labor itself causes the abundant blessings that follow.
Our culture highly values achievement, and it confers various kinds of reward for academic and scientific excellence. But the world is interested in results, not in the effort expended. If one person of limited capacity were to labor continuously at a given project without achieving success, while another person who is extremely gifted achieves success in the project with a minimum expenditure of effort, the latter will reap the reward. This is not the Jewish attitude. The Talmud states, "Reward is commensurate with effort." In the study of Torah, in the performance of mitzvos, and in the development of character, God measures virtue not by how much we accomplish, but by how hard we try.
The Talmud further states that not only are people rewarded for extreme effort; they are also blessed with those very goals for which they have worked. They receive not only the many material blessings listed in the chapter cited above, but also the spiritual goals for which they strove, and which might not have been attainable through human effort alone.