Irenaeus on theosis

“...long before Arius appeared on the scene to propose a created savior, it is evident that Irenaeus has already seen and identified the exigency which both Athanasius and the Cappadocians will exploit in developing their cases against Arius and Eunomius respectively, to wit, that for the final beatitude of human salvation to be secure eternally (unlike Adam's 'infantile' and capricious possession of the same), it must involve a participation in or union with the immutable, eternal God.”—Theosis, page 99