St. Irenaeus of Lyon

This work of Christ, the mediator, extends far and wide, infinitely; if so, then the beginning and the course of all history is to be understood in Christ: 'Finem coniungens initio et significans quoniam ipse est qui omnes gentes exinde ab Adam dispersas et universas linguas et generationes hominum cum ipso Adam in semetipso recapitulatus est.' – 'He [St. Luke in the genealogy], linking the end to the beginning, shows that it is He [Christ] who summed up all peoples going out from Adam, scattered, and all the languages and generations of man, including Adam himself, he summed up all this and these in Himself.' (St. Irenaeus: Adversus Haereses III 22.3) There is an obvious ontological meaning to what St. Irenaeus says. But there is also this epistemological, revelatory side to it: Understanding everything in Christ, and understanding it rightly only thus. St. Irenaeus has an extremely prominent place in early Christianity, in the second century. He is – as a disciple of the Apostle-disciple St. Polycarp, but also via contact with others who had direct contact with St. John the apostle and evangelist – a witness of earliest Christianity. And then – in comparison to a lot else in the second century – an impressive amount of his writing has come down to us. His huge text-mass Adversus Haereses is one of the very great things. Detailed engagement with his work is academically very promising; real findings are really well possible here. He is one of the very early and very great sources, with him we truly go ad fontes.