Peter, in showing that the Church is one and that only those who are in the Church can be saved, said: "In the Ark of Noah certain persons, numbering only eight, were saved by water, which Baptism effects in like manner for you" (1 Peter 3:20). He proves and demonstrates that the solitary Ark of Noah was the figure of the One Church. If, at the time of this Baptism of the world anyone could have been saved without having been in the Ark of Noah, then he who is outside the Church could now be brought to life by Baptism.
CyprianBy the help of the water of new birth, the stain of former years had been washed away, and a light from above, serene and pure, had been infused into my reconciled heart, — after that, by the agency of the Spirit breathed from heaven, a second birth had restored me to a new man.
CyprianIf, in the case of the worst sinners and those who formerly sinned much against God, when afterwards they believe, the remission of their sins is granted and no one is held back from baptism and grace, how much more, then, should an infant not be held back, who, having but recently been born, has done no sin, except that, born of the flesh according to Adam, he has contracted the contagion of that old death from his first being born. For this very reason does he [an infant] approach more easily to receive the remission of sins: because the sins forgiven him are not his own but those of another
Cyprian