“All Scripture is inspired by God and is profitable for teaching, for rebuking, for correcting, for training in righteousness, so that the man of God may be COMPLETE, equipped for EVERY good work” (2 Timothy 3:16-17).
Indeed it is.
The New Testament was written by, for, and about Catholics. This verse does not say that the Scripture is complete. It says that Scripture is “profitable”. Now, who is to be doing this teaching, rebuking, correcting and training? Not the text, as these are tasks that belong to persons, not writings, however Holy.
he gave gifts to his people.”
" 11 The gifts he gave were that some would be apostles, some prophets, some evangelists, some pastors and teachers, 12 to equip the saints for the work of ministry, for building up the body of Christ, 13 until all of us come to the unity of the faith and of the knowledge of the Son of God, to maturity, to the measure of the full stature of Christ. " Eph 4
Jesus did not set it up so that people would read the Bible, and attempt to equip themselves for the faith. Instead, before a word of the NT was ever written, he placed people in charge of these duties. It is their job to equip the saints for the work of the ministry, and guide us into maturity in the faith. Scripture is profitable in the hands of those that God has gifted for this purpose.
Good fruit comes from being attached to the vine, which is Jesus.
Another thing that we can agree upon! Jesus is Head of His One Body, the Church, which He has promised to guide into all Truth. This is why we call the Church our Mother. She is His Holy Bride, and His building, into which he has grafted us as living stones.