Concept

Brit Milah ברית מילה

Circumcision on the eighth day—the sign of the covenant made with Avraham and his descendants forever.

Brit milah was given to Avraham in 2047, at ninety-nine: "it shall be a sign of the covenant between Me and you". He circumcises himself, the thirteen-year-old Yishmael and his whole household in one day. Yitzchak is the first circumcised on the eighth day, and that has been the rule since—even on Shabbat or Yom Kippur; only the child's health delays it.

The sages note the paradox: the sign of the covenant is made by a human being, on the body—the completion of creation handed to man. Midrash records Turnus Rufus asking Rabbi Akiva whose works are finer, God's or man's, and Rabbi Akiva answering with ears of grain and a loaf of bread.

Antiochus and Hadrian both forbade it, and it was precisely what people kept doing in secret.

On the timeline

2047 · 1714 BCEThe Covenant of Circumcision, the Visit at Mamre and the Destruction of Sodom 2048 · 1713 BCEThe Birth of Isaac and the Sending Away of Hagar and Ishmael 2488 · 1273 BCEThe Entry into the Land under Joshua and the Fall of Jericho 3593 · 168 BCEAntiochus IV and the Decrees against the Torah 3895 · 135 CEHadrian's Persecutions and the Ten Martyrs

Abraham Isaac Rabbi Akiva Elijah the Prophet Halakha The Torah (Pentateuch)Conversion (giyur)Bar and bat mitzvah Mohel

Sources

Tanakh

Bereishit 17 — the covenant with Avraham and the commandment of the eighth day
Vayikra 12:3 — the repetition of the commandment in the Torah

Chazal: Mishnah, Talmud, midrash, Zohar

Shabbat 130a — a commandment accepted with joy endures
Midrash Tanchuma, Tazria 5 — the argument with Turnus Rufus: human deeds complete the creation

Acharonim and later rabbinic literature

Shulchan Aruch, Yoreh Deah 260–266 — the laws of circumcision

Basis: tradition.