The Jews

God had made a covenant with Abraham and his son Isaac and with his descendants after him: the Israelites. They are called Israelites because they are descendants of Israel, the name God gave Jacob, the son of Isaac (Genesis 32:28). The circumcision of the flesh is the sign of the covenant. Jacob had twelve sons, founders of the twelve tribes of Israel. God made the promise to Abraham that all the nations of the earth would be blessed in his seed. Now Jesus Christ is his seed; it was conceived by the Holy Spirit in the womb of Mary, Joseph's wife, Joseph being a descendant of Abraham. And Jesus Christ came from God. Moses told Jesus about the Israelites. Moses told the Israelites that God will raise up a prophet like him that they will listen to:

The Lord your God will raise you up from among you, from among your brothers, a prophet like me: you listen to it! (Deuteronomy 18:15)
I will put my words in his mouth and he will convey to them whatever I command him. And if someone refuses to listen to what they say about me, I will ask them to account for it myself. (Deuteronomy 8:18)

God established a new covenant with men through Jesus Christ, learn more . new alliance, circumcision is that of the heart and no longer that of the flesh. (Romans 2:28 and 29)

Under the old covenant the people of God are circumcised in their flesh, under the new covenant the people of God are those who received salvation in Jesus Christ and are circumcised in their hearts, from the ciconcision of Christ.