If God really is unchanging — the same yesterday, today, and forever — both Old and New Testaments must be continuous and thematic. We believe in one God, right? Scripture quoted by Jesus and the apostles to teach us about God and his will was our Old Testament. We believe it is the Word of God, right?
The story begun in the Old Testament is fulfilled and brought to its grand climax in Jesus. But Jesus explicitly said he had not come to abolish or cancel what had come before. So why had I been so careless with it? I have come to realize that I cannot know the God who was incarnate in Jesus of Nazareth apart from the story whose roots are in Abraham, Israel, and the Old Testament story. "But aren't Christians 'grace and faith' people instead of a 'law' crowd?" asks someone. That's what I always heard back in those young and formative years. And I think it was that perspective — today I would call it a "caricature" — that led me to think reading the Old Testament wasn't really all that important.
The Bible is a single volume with a single central character and theme. The written Word of God points readers to Jesus of Nazareth for the sake of offering us salvation by grace through faith in him. It is a single consistent narrative. And the last pages are best read with the perspective of the opening ones in mind.
The perfect display of God's grace in Jesus is set in the Bible's rich narrative of grace to Israel. Yahweh creates and blesses this good world, calls Abraham and his offspring (i.e., Israel) to be the shining exemplar of faith to all people, rescues Israel from oppression in Egypt, calls that rescued group to be his covenant community, and graciously preserves it through both the opposition of its enemies and its own failures. That narrative is the story of all human history and every human life. Its climactic moment comes in the gospel of Jesus Christ.
If I had realized all this much earlier than I did, I would have known more stories than Noah's Ark, David and Goliath, and Daniel in the Lions' Den. Okay, maybe a few more! But reading the Old Testament as the opening acts to a single, grand story of God's redeeming grace was a late discovery. And grand! As John wrote in opening his Gospel (1:17), the fullness of grace and truth we discover in Jesus brings to completion the story Moses began writing in Torah.
Would you read any other good book of 500 pages by starting on page 335? This one is the Good Book and certainly deserves as much from its readers.