In Parshat Tazria, Vayikra 12:3, we learn about the mitzvah of brit milah, circumcision: "And on the eighth day the flesh of his foreskin shall be circumcised."

Why is the Torah repeating the mitzvah of brit milah here when it has already been commanded to Avraham in Parshat Lech Lech, Breisheet 17:9-14? In Breisheet 17:10 God commanded Avraham: "This is my brit (covenant), which you shall keep, between me and you and your seed after you. Every baby boy shall be circumcised".

According to Radak, it is clear that the commandment to Avraham included Yitzchak and Yaakov and the future generations as well.

Nechama Lebowitz quotes the Or HaChaim in stating that the reason why the commandment of brit milah is reiterated in our parsha is to teach that brit milah is done on the eighth day, even if it is Shabbat. Why wasn't this included in the commandment to Avraham? Or HaChaim answers that since Avraham was not commanded in the mitzvah of Shabbat, it wouldn't have made sense to include the obligation to perform a brit milah even on Shabbat.

The wicked Turnus Rufus asked Rabbi Akiva why the baby boys aren't already born circumcised. Rabbi Akiva answered that God gave us the commandments in order to refine our character through them.

What does the mitzvah of brit milah emphasize? According to Sefer HaChinuch, brit milah draws attention to the fact that God did not create men in a perfect state from the womb. God wanted to teach us that just as perfection of man's physical form is by man's own hand, so does it lie in his hand within his means and power to complete his spiritual form by the worthiness of his actions.

We learn from the mitzvah of brit milah that through our actions we have the opportunity to perfect ourselves and the entire world both physically and spiritually.