The Role of Bishops in Protecting the New Testament

The bishops protected the New Testament through this collection of original records in the churches that unfolded the role of bishops and their teachings. This is an amazing thing that's happening here. These churches knew what they were doing. They knew how to protect their own. And where do they learn that from the apostles who were facing it when they were alive, set up a chain of custody that would be unbreakable if followed?