How do you get from London to Edinburgh? Even if you’ve never visited either city, you’ll likely know that there’s more than one answer to the question. Plug the destinations into a maps program and you’ll be offered a host of routes, and even those will be just the major ones. In reality, there are thousands of connections between the two capitals, an almost endless number of ways you can travel between them. Of course, some are more obvious than others, the large motorways cutting a clearer trail than the winding country roads. But the point remains: there are many ways to make the journey.
When it comes to Scripture, what links Genesis to Revelation? We know that the Bible is one book, giving a coherent, unified message. It is, ultimately, the product of one Author, revealing one way of salvation to mankind. But is there only one theme that binds the Bible together? The answer, surely, is no. Just as on any other journey, there are multiple paths we might follow as we trace God’s great redemption story. To change the image, Scripture is a book woven together by many threads, a rope of many intertwining cords. To search for “the one theme” of the Bible is a pointless exercise; rather, we can enjoy discovering dozens, perhaps hundreds, of different melodies that combine to create the final symphony.
Let’s consider some of the major roads. It’s sometimes noted that the Bible nowhere uses that common evangelical phrase “relationship with God.” This is not, of course, because there is no relationship with God. Rather, the Bible’s word for that bond between Jesus and His people is covenant. Unsurprisingly, therefore, covenant is a major road through the pages of Scripture. Beginning in the garden of Eden, God entered into a covenant with Adam. Although the explicit word covenant doesn’t appear in the text of Genesis 2, all the elements that make up a covenant are there: the two parties (God and Adam), the terms of the relationship (wholehearted obedience, expressed in the command not to eat of the Tree of Knowledge of Good and Evil), penalties if the covenant is breached (death), and rewards if it is kept (eternal life, symbolized by the Tree of Life; Gen. 3:22). Indeed, Hosea later refers to this arrangement as a covenant (Hos. 6:7).

Romans 13:1, which says, “Let every person be subject to the governing authorities.” Looking at that one text alone, someone might argue that if the particular government they are subject to orders them to bow to an idol, they should do so. It seems, at first glance, to be a “necessary” consequence of the command to obey rulers. But even a superficial knowledge of the rest of the Bible shows that this wouldn’t be a good consequence; we have clear texts forbidding idolatry. So, while the “logic” of Romans 13:1 might lead our friend to think he is being obedient in bowing down to an idol, as people under God’s Word, we know that this is faulty reasoning. Not all seemingly “necessary” conclusions we draw from a particular passage are good—not least because our minds are limited and clouded by sin.

I don’t see the word Trinity in the Bible,” says the Jehovah’s Witness knocking on your door. “There are no Bible verses that say we shouldn’t speed,” argues the angry church member who’s been pulled over by the police for the tenth time. “I can’t see a clear example of a woman taking the Lord’s Supper in Scripture,” worries the newly converted single mom. And they’re right, aren’t they?

As evangelicals, we rightly want to be people of the Word. We treasure the Bible as the Spirit-breathed Word of God. We acknowledge it to be without error, sufficient for our every need as disciples. We recognize it as our supreme authority, coming, as it does, from our Lord and King. But is this authoritative Word limited to the words of the text alone? Our Reformed forefathers thought not. Take this paragraph from the Westminster Confession of Faith: “The whole counsel of God concerning all things necessary for his own glory, man’s salvation, faith and life, is either expressly set down in Scripture, or by good and necessary consequence may be deduced from Scripture” (WCF 1.6).
The key phrase for our purposes is, “by good and necessary consequence may be deduced from Scripture.” Put simply, this means that not just the explicit text but also those truths that unavoidably arise from the text are also part of the meaning of God’s Word. So, consider our speeding driver. Is there a specific Scripture on speed limits? Clearly not. But if we consider our duty to obey those earthly authorities God sets over us (Rom. 13:1–7), we are justified in claiming that it is not just the police but God who wants us to obey speed limits. Is there an explicit example of a woman eating the Lord’s Supper? Perhaps not. But once we’ve carefully put together texts on the place of women in the church and the purpose of the supper, we should conclude not just that Christian women may take communion, but that they must unless they are under church discipline. All other things being equal, it would be wrong to refuse to admit to the supper on account of their gender someone who credibly professes faith in Christ or for our nervous newly converted mom to abstain.
But the particular concern I want to address in relation to “good and necessary consequence” is pastoral. Namely, we must learn to distinguish between “good” consequences and “necessary” ones.