Taught by the Apostles
"The Church," wrote Irenaeus, "having received this preaching and this faith, although scattered throughout the whole world, yet, as if occupying but one house, carefully preserves it. She also believed these points [of doctrine] just as if she had but one soul, and one and the same heart, and she proclaims them, and teaches them, and hands them down, with perfect harmony, as if she possessed one mouth."
From the beginning, Christians have been urged to hold on to "the faith delivered once for all to the saints" (Jude 3). Yet also from the beginning, some people had begun to misunderstand or misinterpret that faith. After the eyewitnesses and apostles passed away, believers could no longer go for answers to those who had laid the foundations of the church. In every great city, different teachers and leaders claimed to represent true Christianity, each asserting that they maintained the true faith, each appealing to a body of apostolic writings.
To support their doctrines, some Gnostics were claiming a succession of teachers going back to an apostle. In the face of such authoritative-sounding claims, how could Christians know that what the Gnostics taught was wrong and what their own pastor taught was right? Whom could they trust?
Despite these contending claims, even the pagan doctor Galen (129-216?) recognized that there was such a thing as "the Great Church," which was clearly distinct from the multitude of sects. Irenaeus of Lyons was the first Christian leader to write a confident statement of the faith of "the Great Church" and explain why it could be trusted. He considered three things to be inextricably linked: Scripture (both the Old Testament and the apostolic writings), ...