A man that is an heretic, after the first and second admonition, reject; knowing that he that is such is subverted, and sinneth, being condemned of himself.
Irenaeus of LyonsAnd when we come to refute them, we shall show in its fitting place that this class of men [i.e., the gnostics] has been instigated by satan to a denial of that baptism which is regeneration to God, and thus to a denial of the whole faith [by denying all physical aspects of spirituality, including the incarnatian and bodily resurrection of Jesus].
Irenaeus of LyonsOthers of them employ outward marks ... They style themselves Gnostics. They also possess images, some of them painted and others formed from different kinds of material. They maintain that a likeness of Christ was made by Pilate at that time when Jesus lived among them. They crown these images, and set them up along with the images of the philosophers of the world, such as Pythagoras, Plato, and Aristotle, and the rest. They have also other modes of honoring these images just like the Gentiles.
Irenaeus of Lyons[Naaman] dipped himself," it says, "seven times in Jordan." It was not for nothing that Naaman of old, when suffering from leprosy, was purified upon his being baptized, but as an indication to us. For as we are lepers in sin, we are made clean by means of the sacred water and the invocation of the Lord from our old transgressions, being spiritually regenerated as new-born babes, even as the Lord has declared: "Except a man be born again through water and the Spirit, he shall not enter into the kingdom of heaven.
Irenaeus of Lyons