Do you have any idea what 2 Peter 1:20-21 actually means? It means that no writer of the NT (and the OT for that matter) simply recorded his own explanation of what he had heard Jesus teach and had seen Him do. Scripture does not have "its origin in the will of man (2 Pet. 1:21). The writers of the Bible did not decide that they would write a prophetic record or what would be included in Scripture. Rather, they were "carried along by the Holy Spirit" (2 Pet. 1:21).
The NT Scriptures are much more than a written record of the oral teaching of the apostles; they are an INSPIRED record.
If God's Word of truth were given the FINAL AUTHORITY it deserves, as God's Word of Truth, there would be no "agendas". Of course, that means the Catholic Church would collapse under the weight of tradition, doctrines of men, deceit, and denial of God being the FINAL AUTHORITY OF HIS OWN WORD. The Catholic Church is the very epitome of AGENDA.
