From the very beginning, as St. Matthew testifies (xviii, 17) the necessity for salvation of belonging to the one fellowship was established on the basis of an express saying of our Lord’s: “If a man will not hear the Church, let him be to thee as the heathen and publican,” that is, regard him no longer as a Christian. St. Cyprian afterwards expressed this conviction of primitive Christianity in those clear-cut sentences which have impressed themselves on the memory of Christendom: “To have the one God for your Father, you must have the Church for your mother” (Ep. Ixxiv, 7). “No man can be saved except in the Church” (Ep. iv, 4). “Outside the Church there is no salvation” (Ep. Ixxiii, 21).

Thus was formulated that sentence which puts the Church’s claim to be the only source of salvation in the most concise form: “Outside the Church no salvation” (Extra ecclesiam nulla salus). The Fourth Lateran Council (A.D. 1215) adopted this formula verbatim. In the so-called Athanasian Creed, which the Church admits among her confessions of faith, it is fully paraphrased: “Whosoever wishes to be saved, before all things it is necessary that he hold the Catholic faith. And if a man do not keep this faith inviolate and intact without doubt he will perish.” More unmistakable still is the declaration of the Council of Florence that all pagans, Jews, heretics and schismatics have forfeited eternal life and are destined to everlasting fire.