This article examines the strong Creator–creature divide that Irenaeus held against gnostic monism as an essential building block for his doctrine of participation in God. By deepening the distinction between God and humanity, Irenaeus could then relate the two non-competitively, even allowing the creature ‘promotion into God’. By building participation into his definition of what it means to be creaturely, Irenaeus develops a dynamic anthropology of growth and grace in which the creature participates in Christ to fulfil its true humanity.