2,156. How the Jews Prepared to Accept the Covenant
Hilchos Issurei Biah 13:1
Israel entered into their covenant with God through three actions: circumcision, immersion in a mikvah and bringing an offering.
Hilchos Issurei Biah 13:2
We know that the circumcision occurred in Egypt because, regarding the Passover offering, The Torah tells us “No uncircumcised person may eat of it” (Exodus 12:48). Moshe performed the circumcisions because, except for the Tribe of Levi, the people neglected circumcision in Egypt. Regarding this, Deuteronomy 33:9 says, “They (i.e., the Leviim) upheld Your covenant.”