What is being "preached?" The Scriptures, the inerrant word of God.
That the man of God may be perfect, throughly furnished unto all good works. " -- 2 Timothy 3:16-17"All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
Sounds pretty all-inclusive to me. What more is there to know of our salvation that is not found in Scripture?
God chose to speak to men through the gift of His Holy Spirit who illuminates His holy word.
The church is a group of believers who have been so blessed who glorify God in their understanding and their worship.
Do you think it was pointless, useless, unnecessary, for Christ to build this Church
Christ came to redeem His flock. Believers are "lively stones," not mortar and brick.
to appoint some --- but not all --- as teachers?
Of course God appointed teachers and pastors and elders and all believers.
God did not, however, appoint "another Christ" or a "co-redeemer" or a "dispenstrix of grace."
Neither the church nor the magisterium nor Mary dispenses God's grace. The church is made up of those who have received God's grace through faith in His Son, according to God's good pleasure.
Well, you tell me. You read what was preached in the 2nd, 3rd, 4th centuries and tell me it was all Scripture, ipsissima verba. It certainly was not.
They didn't even settle the list of what written documents were Scripture until the 4th century
Thus the Church developed much of its teachings from oral tradition. Paul told the Corinthians, "I commend you because you remember me in everything and maintain the traditions even as I have delivered them to you" (1 Cor. 11:2), and he gives these instructions to the Thessalonians, "So then, brethren, stand firm and hold to the traditions which you were taught by us, either by word of mouth or by letter" (2 Thess. 2:15).
He even goes so far as to give them this explicit order, "Now we command you, brethren, in the name of our Lord Jesus Christ, that you keep away from any brother who is living in idleness and not in accord with the tradition that you received from us" (2 Thess. 3:6).
Paul told Timothy, "What you have heard from me before many witnesses entrust to faithful men who will be able to teach others also" (2 Tim. 2:2).
Scripture without Sacred Tradition is unscriptural.