This is part of an ongoing series on the Ten Commandments. God’s word reveals to us the laws he requires for living in the world as he has ordered it, and only by living according to this law are we able to flourish and enjoy our creational purpose: to glorify God and enjoy him. This series explores how Christians, whose identity is in Christ and whose inheritance is stored in eternity, should live under and live out the Ten Commandments.
How do we know what God requires of us? Part of the answer is obvious: Scripture reveals God’s moral will throughout its pages and in convenient summaries such as the Ten Commandments. But traditionally Christianity also teaches that we know God’s moral requirements through the natural law.
Natural law is God’s law revealed to us through the created order. We know the natural law through our physical senses, intellect, and conscience. God has put this world together in such a way that human beings perceive his basic moral requirements simply by living in it, observing it, and reflecting upon it. As fallen sinners, we tend to suppress and rebel against this knowledge. But God’s natural revelation constantly impresses itself upon us and no one can escape it.
Natural Law in Scripture
The most famous biblical text speaking about natural law is Romans 1–2. Paul wrote that “what can be known about God” is “plain” to people, because “God has shown it to them” (Rom. 1:19). God’s existence and attributes are “clearly perceived…in the things that have been made.” Thus, all people are “without excuse” (Rom. 1:20) when they despise the “glory of the immortal God” (Rom. 1:23) and commit sins that are “contrary to nature” (Rom. 1:26). Human beings don’t simply have potential to know God through the natural order, they actually know him (Rom. 1:21) and know that sinners “deserve to die” (Rom. 1:32). Later, Paul spoke about gentiles who didn’t have the Old Testament law but had God’s law “written on their hearts, while their conscience also bears witness” (Rom. 2:14–15).
Many Old Testament passages also testified to the natural law long before Paul wrote Romans. Genesis 20 provides a fascinating example. Abraham sojourned in Gerar and feared for his life, so he told his wife Sarah to say she was his sister. The local king, Abimelech, took Sarah into his house. But when he learned the truth, he confronted Abraham and asked him why he had “done to me things that ought not to be done” (Gen. 20:9). Abimelech was a pagan Gentile who had no Scriptures and no special covenant relationship with God. Yet Abimelech knew that there are certain things that people just shouldn’t do to each other, such as pass off their wives as their sisters—whatever their country, culture, or language. Abimelech had enough moral knowledge from natural revelation that he could rebuke Abraham, the man of faith!
Or consider the opening six oracles of the prophet Amos (1:3–2:3). God spoke these messages not against his covenant people Israel but against Israel’s Gentile pagan neighbors. He held them accountable for sins such as slave-trading (Amos 1:6), treaty-breaking (Amos 1:9), and ripping open pregnant women (Amos 1:13). Although these Gentile nations had never received the law of Moses, they evidently knew from natural law that such deeds were heinous. Thus God was just when he judged them for doing them.
A final example is Proverbs, which advises readers about growing in wisdom. Proverbs describes wisdom as embedded in the creation order. God made this world through wisdom (Prov. 3:19–20; 8:22–31) and thus Proverbs calls readers to become wise through observing the world around them, reflecting upon it, and drawing wholesome moral conclusions. For example, consider how Proverbs commends industriousness and condemns laziness. In one text, it tells the sluggard to “go to the ant…, consider her ways, and be wise.” Ants have no commander yet work hard and gather food (Prov. 6:6–11). Elsewhere, the author describes how he walked by a sluggard’s field and noticed how dilapidated it was. “Then I saw and considered it; I looked and received instruction” (Prov. 24:30–34). God put the world together in such a way that it oozes moral instruction. The natural order communicates that certain sorts of conduct promote blessing and prosperity while other kinds of conduct bring trouble.
The Importance of Natural Law
I conclude with two thoughts about why natural law is important for Christians. First, natural law explains why God is just in holding all the world accountable to his judgment. The doctrine of final judgment is one of the core beliefs of Christianity. Although many evildoers escape punishment in this life, God will bring all to account on the last day, both to glorify his own name and to vindicate his people. But God is just and will surely not judge people for doing things they didn’t know were wrong. Since so many people throughout history have never read or heard the Scriptures, how is it just for God to condemn them for their sins? God can justly hold all humans accountable to his judgment because all of them know his righteous will through the natural law.
Finally, natural law helps us understand why God commands the things he does. Why, for example, do the Ten Commandments tell us not to kill or commit adultery? These aren’t arbitrary decrees of God. God commands them because they fit the world he created. Given the kind of creatures God made us to be, these moral rules make perfect sense. God created us in his image, with great dignity—therefore, it’s contrary to nature to murder one’s fellow human. God also created us sexual creatures, designed to find fulfillment sexually and to have children with a single spouse of the opposite sex. Therefore, to seek sexual pleasure outside the marriage bond is wholly inappropriate. To view it from the opposite direction: to honor other people’s lives and to be faithful in marriage is good for us. Such conduct fulfills God’s purposes in making us how he did and avoids the misery and ruin that tend to befall those who resist God’s natural design.
