If Catholics proclaim that EVERYTHING about the Roman Catholic church is Biblical, then why do they need anything at all that has the same authority in their church as the Holy Scriptures do??
I never saw any teaching of the Catholic Church that everything about the Church is biblical. The Church did not come from the bible. It came directly from God Himself. The bible is primarily salvation history. It came from God, through the authority of the Catholic Church.
We know that Jesus is the fulness of revelation, not Moses, not Peter, not Paul, not the bible.
Jesus taught everything to His apostles.
Therefore His apostles knew more about salvation than the bible.
Jesus commanded His apostles to “proclaim the Gospel”
This Gospel that the apostles preached, which came from Jesus (who is the fulness of salvation) is the source of all saving truth and moral discipline. CCC
Notice it is NOT the bible that is the source of all saving truth, but the Gospel. Because the Gospel came from Jesus who is the fullness of revelation.
Jesus said in Mark 16:26, that those who believed the Gospel the apostles preached would be saved and those who did not believe would be condemned.
Jesus did not say that those who believed the bible, or believed scripture would be saved. Believing scripture is necessary, but not sufficient, since it is not the fullness of revelation.
The Gospel the apostles taught, (handed down in Tradition) was the Catholic faith.
The four gospels are narratives of the life of Jesus. The NT is basically salvation history.
There is not a single paragraph, not a single chapter, not a single book of the bible that claims to be a summary of the Gospel the apostles taught and preached.
In other words, no one can learn the Gospel by reading the bible.
The Gospel the apostles taught and preached was the Catholic faith. That is why all the early Christians who learned from the apostles were Catholic.
The Catechism is the Gospel the apostles taught and preached, adapted to todays problems. The Catechism is the living Tradition the apostles taught and preached.
The Catholic Church is the product of the Gospel the apostles handed down.
Therefore the Catholic faith has much more of God’s teachings than scripture does.
Scripture has much more information on salvation history than the Catechism (Tradition).
Only the apostles and their successsors have divine authority to interpret both