“For the way of all those who see is single and upward, illumined by the heavenly light, but the ways of those who do not see are many, dark and divergent; the one leads to the Kingdom of Heaven, uniting man to God, while the others lead down to death, separating man from God. Thus it is necessary for you and for all who are concerned about their salvation to make [your] way by faith, without deviation, surely and resolutely, lest, in slacking, you remain in gross desires, or, erring, wander far from the right [path]” (On the Apostolic Preaching, 1; translation by John Behr).
Note what seems to be a reference here in St. Irenaeus of Lyon’s work On the Apostolic Preaching to the teaching concerning the Two Ways, as found in Barnabas and Didache. As this is a “summary memorandum” (λαιωδης υπομνημα, 1), in Irenaeus’ words, of the Apostolic Preaching, the related expansions of each, the Way of Life versus the Way of Death, are curtailed, and the connection with the Two Ways material as we know it more fully from Barnabas and Didache is implicit rather than explicit. But it is striking that this is the beginning of Irenaeus’ work on the Apostolic Preaching, being preceded solely by the address to the recipient. Surely the two draw from the same source, and indicate that this was the initial instruction for catechumens. As both Barnabas and Didache indicate, the Two Ways was considered to be a part of the traditional instruction, the “Apostolic Preaching,” originating with the Apostles themselves. This, another of the earliest works preserved to us in our literary inheritance of sub-Apostolic Christianity, clearly shows its reliance upon that Apostolic body of Tradition, taking for granted that a reader will recognize the reference to the “ways” as related also in Barnabas and Didache.