When God entered into a covenant with Abram, He swore to make Abram exceedingly fruitful, that His special relationship with him and his descendants would endure forever, and that he would give him and his descendants (through Isaac, it is later confirmed) “all the land of Canaan as an everlasting possession.” (Genesis 17: 6-8)

The part of the covenant Abram and his offspring were to keep was to circumcise all baby boys at eight days of age. The circumcision is the sign of the covenant.