This week's Torah portion is called Ekev (Since). Moses continues speaking to the Jewish people about how they should cultivate their relationship with God and says, among other things, that this relationship is beneficial to them. Our sages say that the reward for observing the commandments (except in a few specific cases) is in the World to Come. However, the Torah itself does not mention the World to Come. Moreover, as we can see at the beginning of this Torah portion, the blessings and benefits of keeping God's commandments are material (see Deuteronomy 7:13). Some explain this apparent contradiction by saying that the Torah speaks only of the World to Come; that is, when the Torah says "Earth," it is not referring to the physical earth we know, but to a spiritual realm called Earth. The Torah speaks directly about the highest spiritual realms, and we derive teachings and guidance for this material world.
In any case, the benefits of Torah observance cannot be measured individually, since each person has a different opinion about what is beneficial for them. We must find a common parameter for all human beings that we can define as beneficial. Even then, that benefit manifests itself differently in each person.
Our sages say (Pirkei Avot 4:2): "The reward for a mitzvah is a mitzvah." This phrase can be understood in several ways. We can say that when a person fulfills a divine precept, God gives them the opportunity to fulfill another; therefore, the reward for a mitzvah is another mitzvah.
However, there is a deeper explanation: the reward of each mitzvah is the energy it generates in two ways. On the one hand, there is the reward stored up for the World to Come. Each commandment is like a coin placed in a piggy bank, accumulating and, at the appropriate time, bearing fruit. On the other hand, the energy generated by each mitzvah is the harmony between body and soul. The reward of the mitzvah is the mitzvah itself; it is the observance itself that brings peace and satisfaction to the individual. This benefit is something tangible, practical, and real for everyday life. That is why the Torah is called the Torah of Life, because it is a teaching and guide for daily living.
Now, someone might ask, what harmony comes from eating kosher, observing Shabbat, or affixing a mezuzah? This is clearly a question born of an inclination toward evil, a question whose sole purpose is to avoid even trying... as the verse says (Tehillim 34:9), "Taste and see that God is good." Can God be "tested"? Clearly, the psalmist is saying, "Taste God's commandments and see that God is good.".