Why do we need a brit mila? Do we think that Hashem’s work needs improvement?
The Midrash explains:
What is superior, bread or grain? Obviously, the bread is superior, but by stating that, are we stating that the creation of man is superior to that of Hashem? Hashem fashioned the world for us to perfect it. He created grain for us to turn it into bread, He created vegetables for them to be cooked, etc. Moreover, He created man, and by performing brit mila, we perfect man. Then why didn’t Hashem just make man born circumcised? Then, you must also ask “why Hashem left the umbilical cord attached to the newborn, leaving it for man to sever.” Again, Hashem created the world for us to perfect it, so when a child is born imperfect, Hashem gives man the opportunity to perform mitzvot that allow us to elevate our souls and thereby perfect ourselves.