"Tatti, I finished the typing you asked me to do for you," Dovie announced.
"Thanks, Dovie," his father replied.
"You told me that your office will pay me. How much will I get?"
"They'll look at the work, and they'll let you know."
"I want them to know that there was a lot of work. It's true, a professional secretary might have done it faster, but still, you gave it to me at 8 o'clock at night. At that time of day, you can't find a secretary. I did my best...."
"Don't worry, Dovie," his father assured him. "I'm sure they will consider not only the amount of work, but also the late hour, and the effort you put into it."
Parshas Eikev begins by telling us that HaShem promises: "It will come to pass if you listen to these laws... that Hashem... will keep His covenant.... He will bless... the fruit of your land, your grain, your wine, your oil, the calves of your herds, and the lambs of your flocks."
Is having all these things the way HaShem rewards us for keeping the Torah and its mitzvos?
No. Pirkei Avos teaches us: Sechar mitzvah, mitzvah - the reward for keeping a mitzvah is the mitzvah itself. Every mitzvah connects a Jew to HaShem forever. That is the greatest reward that can be given.
To put it another way: The reward of a mitzvah is the chance to fulfill another mitzvah in the future. As another mishnah in Pirkei Avos says: mitzvah goreres mitzvah - "One mitzvah leads to another."
Why then does the Torah tell us about all the things HaShem promises to give us for keeping mitzvos? The Rambam explains: "If you serve HaShem with happiness and observe His way, He will grant you these blessings... so that you will be free to gain wisdom from the Torah and occupy yourself with it."
HaShem does not grant us blessings in payment for the mitzvos we do. Just like HaShem Himself is Ein Sof, so are His mitzvos. And so the only fair payment for them is the mitzvah itself - or a chance to fulfill another mitzvah.
But like the people at Avi's father's office who were going to take into account all the effort he put in, HaShem appreciates our effort. He sees that we are doing our best and working hard to perform His mitzvos. So He says: I will make it easier for you. I will bless your households and businesses, so you will not have difficulties. You will be able to devote your time and energy to mitzvos.
So the rewards that HaShem gives us with these blessings is really the ability to keep on doing more and more mitzvos.
(Adapted from Sefer Sichos 5749, p. 641ff)