"Against Heresies" is a significant work by Irenaeus, an early Christian theologian, written around 180 AD. The text primarily addresses and refutes various heretical beliefs that were emerging in the early Christian community, particularly those associated with Gnosticism. Irenaeus emphasizes the importance of apostolic tradition and the teachings of the Church Fathers to maintain the integrity of Christian doctrine. In this work, Irenaeus outlines the core beliefs of orthodox Christianity and contrasts them with the teachings of heretical groups. He argues for the unity of God and the significance of the Incarnation of Jesus Christ, asserting that true knowledge of God comes through faith and the teachings passed down from the apostles.