5.5% of the Bible is for us today found in the books of the Bible, Romans thru Philemon.
We today are also saved by grace thru faith...however, today, our works play no part in our salvation, whatsoever! (and within these books, Romans thru Philemon, 30% is the Apostle Paul dealing with his kinsmen the Jews).
Are you confused yet? Well, this why God tells us to "study", II Timothy 2:15 (KJB).
Almost all of Christianity has mixed God's doctrine for Israel, with doctrine that is for us today, to a point where most of today's Christianity is nothing more than a "made up" Christianity, which saves no one!
The Apostle Paul's declaration of the gospel, 1 Corinthians 15:1-4 (KJB), and also, in whom you trust, Ephesians 1:12,13 (KJB), after believing Christ's death, burial, and resurrection, for payment of all your sins.
The King James Bible - Pure Cambridge Edition - is "all authority".
There are those who call God's word in the KJB, "final authority".
But, "final authority" means then, that there are other authorities leading up to it, which there is not!
A Message on Hell - The Forgotten Place
Hell - Luke 16:19-31
The life of a lost person, without Christ.
The final destination of a lost person, without Christ - The Lake of Fire
Salvation From Hell
God's Gospel Tract - Romans Chapters 1 thru 4
Why you need to learn to "rightly divide the word of truth" 2 Timothy 2:15
(learning to put bible truths into their proper time slots)