4. This full and living Gospel was handed down entirely in Tradition.**
The Church teaches in the Catechism:
[size=2]“In order that the full and living Gospel might always be preserved in the Church the apostles left bishops as their successors. They gave them their own position of teaching authority.” Indeed, “the apostolic preaching, which is expressed in a special way in the inspired books, was to be preserved in a continuous line of succession until the end of time.” This living transmission, accomplished in the Holy Spirit, is called Tradition, since it is distinct from Sacred Scripture, though closely connected to it. Through Tradition, "the Church, in her doctrine, life and worship, perpetuates and transmits to every generation all that she herself is, all that she believes."3[/size]
1Redemptoris missio, 5
2Catechism of the Catholic Church 75, Council of Trent, session 4.
The “full and living Gospel” is handed down entirely in Tradition. Thus, “all that she believes” is handed down entirely in Tradition, not scripture.[LIST=1]
*] [size=2]Again, scripture is a witness to this. First,[/size] Jesus commanded His apostles to preach this Gospel that they learned from Him. He did not command them to write the Gospel they learned from Him. Second, the apostles had to take Jesus as an example. Since Jesus did not write a word of scripture when He taught the Gospel, the apostles had to follow His example and also proclaim the Gospel without writing a word of scripture. And since Jesus taught them EVERYTHING, they had to teach their successors EVERYTHING.[/LIST]There is not a single book of the Bible, not a single chapter of the Bible that claims to be a summary of this Gospel that the apostles taught and preached. Therefore we cannot learn it from reading the bible. It must be proclaimed by the Church. 875.[LIST=1]
*] “How are they to believe in him of whom they have never heard? And how are they to hear without a preacher? And how can men preach unless they are sent?” No one - no individual and no community - can proclaim the Gospel to himself: “Faith comes from what is heard.”[/LIST]So faith comes from what is heard, no one can learn the Gospel by studying scripture.
Later on the Holy Spirit moved some apostles and apostolic men to write the narratives of the life of Jesus, the four Gospels. The Church teaches that “The sacred authors, in writing the four Gospels, selected certain of the many elements which had been handed on…”1
These narratives of the life of Jesus are also called “Gospels” because they contain certain of the many elements of the “full and living Gospel”, but they do not claim to be a summary of the Gospel the apostles taught and preached.
The reason the Church says scripture always must be interpreted according to Tradition, is because ONLY Tradition contains the full entire Gospel that Jesus taught to His apostles. Scripture only contains “certain elements” of this Gospel, and these certain elements are seldom clear.
So what was the content of this Gospel the apostles taught and preached?
Since Jesus said salvation comes from believing this Gospel, and not from reading scripture, we must know the content of this Gospel.
Now, even an atheist can know exactly the content of this Gospel the apostles taught, even though they never wrote it. It is easy, all we have to do is learn the teachings the early Christians learned from the apostles. If we read what they wrote, we notice that they all believed in the Real Presence of Jesus in the Eucharist, the mass, prayers to the saints in heaven, the authority of the Church, etc. In other words, the early Christians who learned directly from the apostles believed the same teachings the Church teaches today. In other words, the early Christians who learned from the apostles were all Catholic. So the Gospel the apostles taught was the Catholic faith.