In Perek 13, Hashem commands Moshe on the Mitzvot of Pidyon Haben, Pesach, and Tefillin. Pasuk 2 introduces the Perek commanding Moshe to consecrate all the first borns, man, and animal, to Hashem. In Pasuk 3, Moshe then commands Bnai Yisrael to do the Mitzvot listed in the Perek.
Rambam comments that this Mitzva of consecrating the human Bechor applies only to the generation of Moshe, while all the other Mitzvot are eternal Mitzvot. In addition, Pesach is a Mitzva kept exclusively during the spring.
Rav Shimshon Rafael Hirsch says that usually when Hashem commanded Moshe to do something Moshe would then teach it to Bnai Yisrael and we would know about it today based on the Mesora. But since this was only the second Mitzva commanded to Bnai Yisrael, the Torah gave an example of how a Mitzva is passed down by recording what Moshe said to Bnai Yisrael.
However the question arises, what is the connection between what Hashem commands Moshe and what Moshe tells Bnai Yisrael? Why does Moshe only tell Bnai Yisrael about the first borns later on if it was the only commandment he was told about? Rav Hirsch explains how the chronology of Perek 13 works out following Hashem’s commandment. Pasuk 3, which according to Rashi is the source for remembering the redemption daily, shows how all of Bnai Yisrael were freed from the Egyptians. With the consecration of the first borns, some Jews may have thought that only the first borns play a role of holiness in Klal Yisrael. So, Pasuk 3 reminds them that all of Bnai Yisrael are equal because Hashem took all of them out of Egypt.
Furthermore, not only were Bnai Yisrael physically redeemed in the spring, their they are also symbolically similar to the spring. During the spring new plants sprout but their fruits don’t immediately ripen. Similarly, Bnai Yisrael sprouted with their freedom, but only their living in Israel will enable their fruits to ripen. This is why we are allowed to make changes in the calendar to influence when Pesach will fall out. Pesach is a holiday resembling spring and ripening, and for one week every spring we bring about this process of ripening by remembering what happened in Egypt. During this time we are only allowed to eat Matza because it symbolizes a slave’s meal, and while before we were slaves to the Egyptians, now we are “slaves” to Hashem.
After Moshe tells Bnai Yisrael how to serve Hashem, he tells them about educating the children so they can follow in their fathers’ footsteps. According to Rav Hirsch, the consecrating of the first born, which Moshe talks about last when speaking to Bnai Yisrael, only ensures Bnai Yisrael that we all must live a life of service to Hashem. The first-born are only the first ones to be consecrated to Hashem, but all future children will be consecrated.
Every Jew has full obligation to Hashem, and although one may find many disparities between him and others both in characteristics and ability, everyone has an equal obligation to perform what is commanded of him. A Jew observing Mitzvot will influence others to do the same, and in this way every Jew is like a fruit bearing tree.