Peter wrote (2 Peter 3:16) that Paul could be hard to understand. I don’t know why he didn’t say the same thing about John. In 2 John 9, we read, “Anyone who runs ahead and does not continue in the teaching of Christ does not have God; whoever continues in the teaching has both the Father and the Son.”
Obviously, there is a development of doctrine that takes place over time. It took over four hundred years for the Church to hammer out the doctrines related o the Holy Trinity and the dual nature (human and divine) of Jesus Christ. We believe that this development is guided by the Holy Spirit.
What I want to be able to say is this: that the development of doctrine does not introduce new elements in to the deposit of faith, but rather clarifies the doctrine to exclude incorrect (i.e., heretical) interpretations. Belief in the Immaculate Conception or the Assumption of Mary can be traced back to the apostolic age; belief didn’t suddenly begin when the dogmas were defined in the 19th and 20th centuries. Doctrine might be developed by using schools of philosophy to explain theological truths in new ways, such as when St. Thomas Aquinas used Aristotelian metaphysics to explain the real presence of Christ in the Eucharist (transubstantiation).
Christ himself promised to send the Holy Spirit to lead his Church into all truth. Over time, we have discovered that this works in a negative rather than a positive way. The Spirit does not inspire the Church to proclaim the truth; rather the Spirit prevents the Church from teaching error. This charism of infallibility is focused in the person of the Supreme Pontiff and those bishops who teach in union with him.
Again, as long as we follow the Pope, we should be on pretty safe ground.
As you can probably guess, I tend to look askance at anything that claims to have a new teaching. There are people very dear to me who are involved with a group promoting ideas that are new and supposedly better than anything that has been taught in the 2000 years of Christianity. When asked about this newness, the claim is made that it’s all right there in the scripture (isn’t every heresy?). Amazingly, it took a special revelation for this teaching to be discovered. The Holy See is reviewing it, they claim, and will approve it any day now.
Right. Until that day (I won’t be holding my breath), I think I’ll stick with what I can trust.