I'm not sure which doctrines you are referring to, but there are many doctrines that the Christian church takes for granted today that were not taught in the second century. The fact that certain doctrines were not articulated is not an indication that they were not believed in principle. The source for these doctrines (the teachings of Jesus Christ and the apostles as recorded in the Holy Scriptures) was present from the beginnings of the Church, but the questions that were being asked later, which brought about the revealing of these doctrines from Holy Scripture, were not being asked in the second century. Holy Spirit works at His own schedule and reveals truth at His own discretion. The doctrine of the Trinity was not articulated until the fourth century. I guess you would throw that out as well? How about the vicarious atonement? That was not articulated until the 12th century. You don't believe that either?
And in 1 John 5:7. But yes, the Holy Spirit works as He wills (John 16:13). He works through the Church (1 Tim. 3:15). In the apostolic traditions (2 Thess. 2:15).