The Scripture-alone mentality turns a deaf ear to Sacred Tradition. Indeed, it's reminiscent of the mindset of the 16th-century Catholics who converted to Protestantism. A brief look at where the Bible came from, however, shows the so-called sola Scriptura theory doesn't hold historical water.
For starters, first-century Christians didn't even have all 27 books of the New Testament, as the last book, St. John's Apocalypse, wasn't written till nearly A.D. 100.
During the next four centuries, the Bible-only theory still fails because most Christians didn't know which books were inspired and which were apocryphal. This problem wasn't solved until A.D. 382, when the Church, during a synod in Rome under Pope St. Damasus I, declared which writings belonged in the Bible (Denzinger, §84). This declaration was duplicated in A.D. 397 at the Council of Carthage (Denzinger, §92).
Prior to this, even saints debated which books were part of Sacred Scripture. Fourth-century Father and Doctor of the Church St. Augustine sided with the Church: "For my part, I should not believe the gospel, except as moved by the authority of the Catholic Church."
Another problem was the 73 books of Scripture existed in various languages, including Hebrew and Greek. That wasn't resolved until the early fifth century, when St. Jerome completed the Church's commission of compiling all 73 inspired writings into one language in a single book — the Latin Vulgate.
The scarcity of access to the Vulgate for the next 1,000 years further proves the inanity of the Bible-alone theory. It took a monk several years to hand make a single copy in his monastery's scriptorium. The printing press wasn't invented until the 15th century. This invention made copies of the Bible somewhat more available, but didn't solve the pervasive problem of widespread illiteracy.
It is, therefore, understandable why Christ, in Matthew 28:19, told His first bishops to go forth and teach (instead of write).
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