The Bible consists of 66 different books, written by dozens of people across millennia.
The Bible is one book, written by one author (God the Holy Spirit), conceived in eternity and executed in history.
Both statements are true. In the Bible, unity and diversity co-exist, just like in the Trinity and in the Church. So we must be fair to both.
When we talk about OIA Bible study (Observation, Interpretation, Application), we focus primarily on the diversity of Scripture. Each author of each passage has a unique point to make. We read each text in its context to figure out its main point, connect it to Jesus, and draw applications for today. We’ll get something different out of each passage. Different cultures and different generations will draw different applications from the same main points. That’s okay; in fact it’s beautiful when we see God’s Knowable Word connecting with any person in any culture at any time.
It’s important, however, not to neglect the unity of the Scripture. God the Holy Spirit spoke through each of those different authors. He strategically unravelled the stories and the laws and the poems and the letters in just the right way to reveal the Lord Jesus to the world.
After studying a passage of Scripture, it’s important that we connect what we learned to the rest of Scripture. We call this process Correlation.
For example, Luke 2 teaches about God’s plan to rescue the lowly and rule them graciously through the birth of his Son. But it’s not the only passage that speaks of his rescue or rule. It’s not the only passage that speaks of Jesus’ humanity. In fact, if we treat Luke 2 as though it has the whole truth about Jesus’ embodiment, we’ll come away with a pretty thin perspective.
We’d miss the fact that God wants to be with us (Matt 1:21-23). We’d miss out on the beautiful imagery of God’s residence in the temple: God’s altar, light, water, bread, incense, and private chamber (Exodus 25-40). We’d miss the point that Jesus’ humble birth prepares him for his gruesome death (John 12:27). We’d think that imaging him simply means going to be where people are; we’d miss the corresponding need to call them away from what they’re doing (Mark 1:16-20).
Stephen understood Correlation when he spoke to the Jewish rulers in Acts 7. He didn’t focus on a single Bible passage, but he connected them all together to show how the religious have always rejected the godly.
The author of Hebrews understood Correlation when he wrote of the intricate connections between priest, temple, and sacrifice – and how the whole system finds its fulfillment in Jesus.
John understood Correlation when he wrote his climactic book of signs (we call it Revelation). He pulled together all the imagery of the Bible into one dense letter written to encourage persecuted believers in the Roman province of Asia. John was so skilled at smooth Correlation that many people miss it today. We tend to read Revelation with internet newspapers as our reference guides, and not in light of the other 65 books of the Bible, as John intended (Rev 1:1-3).
In short, Correlation is the process of constructing a systematic theology from the Scripture. We shouldn’t pit one passage against another. Rather, we work to understand how they fit together. As we do so, we get to know the Lord who made himself known in the Scripture.