That unless a man have been baptized and born again, he cannot attain unto the kingdom of God
In the Gospel according to John: “Unless 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 you eat the flesh of the Son of man, and drink His blood, you shall not have life in you.”
Source: The Treatises of Cyprian (New Advent)