A favorite Protestant slogan is “The Open Bible.” This, in turn, becomes the name for many churches and Christian ministries.
And this “Open Bible” philosophy is a basic part of my own Christian theology. What it means for me is that the entire Bible is available to the Christian for moral and theological guidance. If you want to know what the Bible teaches on some particular topic, you simply turn to whichever book or chapter of the Bible that has the most to say about that particular topic.
If you want to know about sola fide, a natural place to start is Romans or Galatians. If you want to know about covenant theology, a natural place to start is Hebrews. If you want to know about church office, a natural place to start is the Pastorals. If you want to know about the life of Christ, a natural place to start is the Gospels. If you want to know about church history, a natural place to start is Revelation. If you want to know about ecclesiology, a natural place to start is Ephesians.
If you want to know about creation, a natural place to start is Gen 1-2. If you want to know about the fall, a natural place to start is Gen 3. If you want to teach boys how to be men, a natural place to start is Proverbs. If you want to know about the laws of warfare, a natural place to start is Deut 20.
There’s no one place to start. No one place you go every time. Rather, you begin wherever you find whatever answer you’re looking for, in whatever book or chapter of the Bible answers your question.
I have a problem when Christians treat the OT like a ladder we kick aside once we reach the NT. That’s the view of Marcion. That’s the view of the Anabaptist. To some extent, that’s the view of the fundamentalist.
It’s also the view of some moderate-to-liberal types, according to whom the OT is less inspired than the NT—that progressive revelation means progression from darkness and error into the bright light of the gospel truth.
That’s not the view of the Presbyterian. That’s not the view of the Reformed Baptist. That’s not the view of the Reformed Anglican.
There are, of course, discontinuities between the Old Covenant and the New Covenant. And where, exactly, or where, even roughly, we draw that line is one of the distinguishing features which differentiates one Reformed tradition from another, as well the Reformed tradition from Christian traditions outside of Calvinism.
A Reformed Anglican draws the lines a little differently that a Presbyterian, and a Presbyterian draws the lines a little different than a Reformed Baptist. This accounts, in no small part, for varieties of Calvinism within the Reformed community.
Most-all of us draw a line where the ceremonial law is concerned, but of course, that, itself, becomes an issue of where the ceremonial law leaves off and the moral law begins. Although we agree on the general distinction, we must still deal with the specific question of how to classify which parts of the law as ceremonial. And every Calvinist is confronted with this question—whether he’s an Anglican, Baptist, Presbyterian, or Xrecon.
For me, sola Scriptura includes whole-a Scriptura—the whole Bible. The Bible is a two-way street. We can go from the OT to the NT, but we can also go from the NT to the OT. The NT writers didn’t detonate the bridge between the Testaments so that we could no longer cross over from one side to the other and back again.
The NT is an open book, but so is the OT. The NT doesn’t close the book on the OT. As long as we make due allowance for patterns of promise and fulfillment—a Christian should not feel any inhibitions about looking to the OT for moral guidance in matters of personal and social ethics. Let's not treat the OT like an "adult" bookstore.
Contrary to Marcion, the God of the NT is the same God as the God of the OT. And the Bible of Jesus was the OT. Indeed, the Bible of the Apostolic church was the OT. The NT does not supplant the OT.
Human nature is the same under both Testaments. Sin is the same under both Testaments. Grace is the same under both Testaments.