Irenaeus of Lyons · a new plain-English translation from the original language
On what sort of persons, and for what cause, are called a brood of vipers — namely, those who do not obey the Gospel.
For just as among men, sons disobedient toward their fathers are disowned — sons by nature they remain, but estranged by law, since they no longer stand as heirs of their natural parents — so likewise, before God, those who refuse him obedience, once disowned by him, cease to count as his sons. Hence they cannot lay claim to his inheritance either; as David says, "Sinners are estranged from the womb; they go astray, in the likeness of a serpent." Because the Lord knew this to be the human condition, he therefore called them a brood of vipers, in that, resembling these creatures, they roam about in their varied ways, doing harm to others; for he says, "watch out for the yeast of the Pharisees and Sadducees." And also, speaking of Herod, he says, "Tell that fox" — pointing to his crafty malice and treachery. For which reason the prophet David declares, "Man, set in honor, has become like the beasts." And again Jeremiah says, "They have become like maddened horses after their neighbors' wives, each one after his fellow's." And Isaiah, preaching in Judea and disputing with Israel, calls the rulers Sodom's and the people Gomorrah's — meaning by this that a like transgression, the very sins found among the Sodomites, were discovered among them, addressing them under that same title on account of their matching conduct. And because they had not been shaped that way by God, by nature, but were capable also of righteous action, he further offered them this sound counsel: "Wash yourselves, be clean, put away your wickedness from your souls before my eyes, cease from your iniquities." Clearly, because they themselves, upon transgressing and sinning, drew the very rebuke the Sodomites had received. For had they turned back and repented and abandoned wickedness, they might have become sons of God, and gained the inheritance of incorruption bestowed by him. On this reasoning, then, he termed them angels of the devil and sons of the evil one, since they trust the devil and do what belongs to him. For indeed, all were fashioned from the beginning by one and the same God. But when they trust and submit to God, persevering and holding fast his teaching, they are sons of God; yet when they fall away and transgress, they are reckoned to the devil as their prince, who first made himself, and then the rest, the cause of falling away.
Since, moreover, the Lord's sayings are many indeed, yet every one proclaims one and the same Father, the maker of this world, it was fitting that we too, for the benefit of those entangled in manifold errors, refute them through many arguments, so that, being refuted at many points, they might somehow turn to the truth and find salvation. It is necessary, however, in this treatise, once the Lord's sayings are covered, to add also Paul's teaching, and to weigh his meaning, and to set forth the Apostle's sense, and to explain whatever readings the heretics — failing utterly to grasp what Paul said — have wrested to their own use, and to lay bare the folly of their want of sense; and, from that very Paul from whom they draw their objections against us, to demonstrate that they lie, while the Apostle proclaims the truth, teaching everything in agreement with the truth's proclamation: that the God who spoke to Abraham, who issued the law, who dispatched the prophets in advance, and who in the last times sent forth his own Son and grants salvation to his own creation — the substance which is flesh — is one God, the Father. The remaining of the Lord's sayings, then — those he taught not through parables but plainly, in unadorned words, concerning the Father — together with a treatment of the letters of the blessed Apostle, we shall lay out, with God's aid, in another volume, and so furnish you the full work of exposing and overturning that falsely so-called knowledge, and shall train ourselves and you against all the heretics, across five books.