Cyprian of Carthage, Three Books of Testimonies Against the Jews III.26: That unless a man have been baptized and born again, he cannot attain unto the kingdom of God

25. That unless a man have been baptized and born again, he cannot attain unto the kingdom of God.

In the Gospel according to John: “Except a man be born again of water and the Spirit, he cannot enter into the kingdom of God. For that which is born of the flesh is flesh; and that which is born of the Spirit is spirit.” Also in the same place: “Unless ye eat the flesh of the Son of man, and drink His blood, ye shall not have life in you.”