The modern-day focus is on the last one - the written word in the Bible
We can study the effects of decrees
addresses are uncommon and difficult to reliably study
similarly, prophets have ceased
What is Canon, and why?
OT:
Basically we trust that the Old Testement we have is accurate, because the people at the time of the NT believed it.
Not just this though, early historians and teachers also validated it.
The things not quoted or referenced are not included, as they are not provably the Word of God.
NT:
Most of the New Testement is written by primary sources; the apostles.
The apostles verify each other
2 Peter 3:16 - Peter verifies Paul
1 Timothy 5:17–18 - Paul references Luke
The rest, and these, were methodically reviewed.
“In A.D. 367 the Thirty-ninth Paschal Letter of Athanasius contained an exact list of the twenty-seven New Testament books we have today.” - Wayne Grudem, Systematic Theology