Against Heresies

Written in the second century as the Church confronted rival gospels, secret teachings, and distorted accounts of Christ, Against Heresies: Book I is Irenaeus’s great exposure of false knowledge. Here the bishop of Lyons names the Gnostic systems of his day, especially the elaborate teachings of the Valentinians, and shows how their myths of aeons, emanations, secret wisdom, and a lesser creator god depart from the faith received from the apostles. Against these private speculations, Irenaeus sets forth the public confession of the Church: one God, one Christ, one faith, and one apostolic tradition held throughout the whole world. Book I is both a map of ancient heresy and a defense of the Church’s common rule of faith — a sober, pastoral work written to preserve the Gospel from being fragmented, hidden, or remade.

• Ante-Nicene Father (c. 130–202 AD)
• Featured in the June 2026 Catechized Book Club
• Companion keepsake: “The Rule of Faith” card featuring Irenaeus’ summary of the apostolic faith.
• 3 book copies currently on hand
• Selected line: “The Catholic Church possesses one and the same faith throughout the whole world.”