1Then God spoke all these words, saying,...Exodus 20:1 NASB
16 All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness; 17so that the man of God may be adequate, equipped for every good work. 2 Timothy 3:16-17 NASB
He's been giving us Scripture for a very, very long time.
That was a typo! What I meant to write was
"The Scriptures are from God."
Surely we all know that.
They come to us through a chain of custody and transmission, just as does everything that was handed down to us.
Otherwise, they would not be here for us today, since none --- not one --- of the original autograph manuscripts is now in existence, as far as we know.
What we have is what came to us through a chain of human beings who, obedient to God and reverent towards His revelation, copied, replicated, annotated, published, translated, laid down their lives to propagate and to defend.
This "handing down" is, literally, Tradition.
And one of the precious things handed down to us from this chain of transmission, this God-pleasing succession of faithful human beings, is Scripture.
And just as the Chosen People existed for a long, long time (how many generations from Abraham to Moses?) before there was a written Torah, the Church existed a long time (many generations) before there was a complete canon of Scripture.
Did you ever consider the fact that Paul urged his local churches to be faithful to the Gospel many times --- surely hundreds of times ---- before one written Gospel even existed?
His converts didn't become Christians because they had read a text and believed some written testimony. They believed because the Gospel --- the Good News of salvation in Christ --- was conveyed he them by preaching (Oral Tradition)---- faith comes from hearing and by the conduct and example of Paul and his many fellow workers.
This was inspired, and authoritative too. Not just the relatively few selections that were written down.