the reason for EVERY Mitzvah is because Hashem commands it, but most Mitzvahs have reasons or taamim, which is the same word as “taste” as well as “reason”
just like we eat to stay alive, but the taam of the food gives us pleasure and helps us to eat, so too we do Mitzvahs because we are commanded but the taam of the Mitzvah helps us to do it and gives us pleasure when we do.