In Nick Needham’s book, 2000 Years of Christ’s Power: The Age of the Early Church Fathers, he covers how heretical teaching impacted the churches, for good and ill. The beginnings of the Gnostic heresies started to rise during the apostles’ lifetime. I think John and Paul dealt with this “proto-gnosticism” in First John and Colossians. Eventually, this heresy gained strength and popularity, and Christians rose to defend the faith. What faith? The faith once delivered (Jude 3; 2 Peter 1:1; Titus 1:4). Though there wasn’t a “Gnostic confession of faith” and different sects had different beliefs, the through line that categorized the movement was Gnostics believed they had knowledge about God that no one else had. Those in the group were privy to insights into spiritual things that no one else knew, and their wisdom was not what the Apostles preached and wrote about. The early churches combated this error by standing on the faith once delivered, not new teaching. They stood in the Apostle’s doctrine, not the Gnostic philosophers. They recognized a unity of faith among the churches that held to the Apostolic teaching and the beliefs held by churches that were started by or had ties to the Apostles. If Antioch and Rome did not have the Gnostic teaching or new knowledge in the second century, it stands to reason it was not something that Paul taught.
Churches distinguished themselves by those who held to the faith once delivered, like the apostles before them, like the churches they founded, and like the Scriptures declare. Many defined themselves as the catholic churches (little “c” catholic). Catholic, universal or around the whole world. They held to the catholic faith, the faith that all Christians believed, as opposed to the new faith and new teachings that the Gnostics believed. But, as time passed, what determined that faith became a tad fuzzy and “what we have always believed” became more rigid, while “catholic” became a invisible and universal church, not doctrine. Traditions became increasingly authoritative, and too much weight was given to influential churches and pastors. Holding to the faith once delivered became holding to the tradition once delivered. What began as a way to combat new errors became the breeding ground for error of another form.
A lot has changed in 2000 years, of course, but some things haven’t changed. The faith once delivered by the apostles, contained in the Holy Scriptures, the danger of going too far in the opposite direction when combating error, and the tendency of people to define what truth is according to their traditions and preferences. “This is the way we always have done it” is not the same as “this is the way Paul did it.” We have the faith, the common salvation that was taught by the Apostles. We have that in God’s Word, not in the traditions passed on to us from the previous generation. Influential pastors of big churches are not the definers of what makes a church a church. History shows us what happens when you drift away from the Word.