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.
Cyprian