God commanded Abraham and his descendants to keep his covenant. They were to circumcise every male child. This was a sign of the covenant between God and Abraham and his descendants (see: Genesis 17:9-14).
Jesus was a descendant of Abraham (see: Matthew 1:1, 16). Paul taught that Jesus fulfilled God’s promise to bless all people through Abraham (see: Galatians 3:8). Jesus did this by dying as a sacrifice so that anyone who believes in him can belong to God.