Jesus’s Legal Theory: Morally Fulsome Lawkeeping
In Matthew 5, Jesus teaches that moral transformation is possible only if all of the Law is kept—outward actions and inward intentions.
Legal systems often distinguish between outward acts and inward dispositions. The American system certainly does. The distinction is operative in First Amendment contexts like free speech and religious liberty. The Supreme Court has said, for example, that the freedom to believe is “absolute” while the freedom to act on one’s beliefs, by its nature, cannot be. “Conduct remains subject to regulation for the protection of society.”
The idea is that only outward acts are subject to legal restriction. Inward thoughts are not. A person may think, believe, desire, and imagine what he pleases, and the law cannot touch him.
But this is a gross overstatement. Legal consequences often flow from a person’s state of mind. Many crimes and civil torts require proof of a person’s intent. In employment discrimination cases, an employer’s motive is relevant to liability. And in other contexts, legal responsibility depends upon a person’s knowledge of something (a dangerous condition on one’s property, for example). Each of these concepts—intent, motive, knowledge—describes an inward state of mind to which the law attaches consequences. This is not usually regarded as controversial.
There are, however, controversial scenarios. Consider the “thoughtcrime” punishable in George Orwell’s fictional 1984, or the recent nonfictional cases of British individuals prosecuted for silent prayer, or American hate crime laws that enhance punishment when the behavior is motivated by racial animus.
In the Sermon on the Mount, Jesus expounds upon a distinction between outward acts and inward thoughts, and uses it to advance his moral agenda:
You have heard that it was said to those of old, “You shall not murder; and whoever murders will be liable to judgment.” But I say to you that everyone who is angry with his brother will be liable to judgment; whoever insults his brother will be liable to the council; and whoever says, “You fool!” will be liable to the hell of fire….
You have heard that it was said, “You shall not commit adultery.” But I say to you that everyone who looks at a woman with lustful intent has already committed adultery with her in his heart. (Matt. 5:21-22, 27-28)
Many read Jesus’s words here as critical of the Law. They see him drawing a distinction between the Law as such and his own teaching: “The Law says X but I say Y.” On this reading, the Law is limited, malformed, and ineffective. Because it regulates only external actions like murder and adultery, it makes people think that only external actions matter. But the thoughts and intents of the heart matter, too. So Jesus offers something new and better. By focusing on the heart, on a person’s inward thoughts—something the Law didn’t or couldn’t do—Jesus institutes a more complete and more virtuous ethical system.
So the argument goes anyway. And the supposed dichotomy between the old Law and Jesus’s new ethic tends to get mapped onto other theological distinctions: old vs. new covenant, works vs. grace, letter vs. spirit, and even Judaism vs. Christianity writ large. In extreme forms, it diminishes the importance of ethical conduct altogether. “It doesn’t matter much what a person does or doesn’t do, so long as they have the right heart.” Or to repurpose a common refrain: “It’s the thought that counts.”
But this dichotomy is a false one, and it misses a crucial point Jesus is making, one that undergirds his legal theory. (For prior essays exploring Jesus’s Legal Theory, see this “Introduction” and this essay on “7 Misconceptions About the Law.”)
The Law was just as concerned with inner thoughts as it was with outward actions. This is everywhere in the Torah.
The Shema (the “greatest commandment,” by Jesus’s reckoning) enjoins Israel to love God with their whole heart, soul, and might (Deut. 6:5). The next verse reiterates: “[T}hese words that I command you today shall be on your heart.” The word “heart” here—Hebrew levav—has a semantic range similar to English, referring to the inner man, the will, the seat of appetites and emotions. (See also Deut. 10:12-16, 11:13, 30:6.)
The Ten Commandments also operate in both dimensions, outward and inward. Murder and adultery are prohibited. But so too is coveting—an explicit regulation of desire. “[Y]ou shall not covet your neighbor’s wife. And you shall not desire your neighbor’s house…” (Deut. 5:21).
Leviticus 19:17 instructs, “You shall not hate your brother in your heart, but you shall reason frankly with your neighbor, lest you incur sin because of him.” The next verse prohibits “bear[ing] a grudge” and famously ends with the second greatest commandment: “[Y]ou shall love your neighbor as yourself.”
The Law does not limit its injunctions to external conduct. It also regulates internal dispositions. It commands heartfelt love of God and neighbor, and it prohibits hateful thoughts and lustful desires. The Law operates upon the whole person—heart, soul, body—envisioning a people who not only conduct themselves outwardly but also form themselves inwardly in a God-given way of life.
So when Jesus says, “Don’t just not murder—also don’t be angry. And don’t just avoid adultery—also avoid lust,” in one sense, he’s simply reminding his listeners of what the Law already says. But I think there are several other things going on here.
First, Jesus is doing constructive interpretive work. When construing a legal text, especially a large and complex one, interpreters strive to read it as a harmonious whole so that its various provisions are rendered compatible, not contradictory, with no provision ignored. Jesus brings together different strands within the Law—conduct-oriented rules and thought-oriented rules—and interprets them in light of each other. He reads the prohibition on murder in light of the prohibitions on hate and grudge-bearing. He reads the prohibition on adultery in light of the prohibition on wrongful desire. Or to put it more succinctly, he reads the Sixth and Seventh Commandments in light of the Tenth. These are not, to Jesus’s mind, separate commands but constituent parts of a harmonious whole.
Second, in relating these commands to one another, Jesus allows the inward-focused commands to function as prophylactics—interior cognitive guardians that protect against exterior ethical transgressions. Take care of what’s inside first, Jesus is saying, and the outside will follow. The converse is also true: sin that’s inside will eventually flow out. There’s an echo here of Matthew 23:25-26: “First clean the inside of the cup and the plate, that the outside also may be clean.” We’ll return to this connection in a later essay.
Perhaps those in Jesus’s day were posing the same kinds of questions people ask today: “Why should the Law care about my internal thoughts, as long as I’m not acting on them? Aren’t my thoughts my own? They can’t hurt anyone. They don’t have social consequences.”
Return to American law for a moment. Consider the U.S. Supreme Court’s 1969 decision in Stanley v. Georgia. Robert Eli Stanley was suspected of being a bookie. In executing a lawful search warrant at his home, officers discovered several reels of pornographic film. Stanley was convicted under a Georgia obscenity law, which made it a crime to possess obscene materials. But the U.S. Supreme Court overturned his conviction, holding that the First Amendment’s protection for free speech prohibits a state from criminalizing the “mere private possession” of such materials. The Court reasoned that “the moral content of a person’s thoughts” is beyond the purview of government regulation because “[o]ur whole constitutional heritage rebels at the thought of giving government the power to control men’s minds.” Georgia countered that this wasn’t merely a “private” matter because what a man views and thinks affects his behavior. But the Supreme Court reasoned that if the state was concerned about behavior, it could regulate behavior; it shouldn’t try to regulate thought.
Both the Torah and Jesus reject the anti-human logic of Stanley v. Georgia. Jesus teaches that the Law is addressed to the whole person. It does not limit its focus to conduct and ignore the intentions of the heart. It places demands upon both because they are interrelated. God doesn’t just want you to act virtuously and avoid sin. He wants you to become the kind of person that loves virtue and hates sin, the kind of person that does the right thing for right reasons.
Third and finally—the most crucial point—Jesus in Matthew 5 is not criticizing the Law. He’s criticizing the failure to keep the Law. The problem is not the Law. The problem is laxity in regard to the Law’s demands. “You may have heard that the Law cares only about your outward actions. But I’m here to remind you that it cares about your heart, too.” Jesus wants his listeners to keep the Law fully, not just partially, because only fulsome lawkeeping will bring about the moral transformation the Law envisions—a virtuous people doing virtuous things according to God’s instruction.
This, in my view, is Jesus’s legal theory: Morally Fulsome Lawkeeping (MFL). It is on full display in Matthew 5, and I believe it provides the interpretive key to the rest of Jesus’s teaching, in Matthew’s Gospel and otherwise. Indeed, the placement in the New Testament canon matters. The Sermon on the Mount is our first canonical encounter with Jesus’s legal discourse,1 and ought to serve as a lens through which the rest of Jesus’s teaching is viewed.
So wherever we encounter legal debate or discourse in the Gospels, we should strive to read it in light of MFL framework that Jesus propounds in Matthew 5. This entails the following three principles, at a minimum:
Lawkeeping: Jesus does not replace or displace or seek to do away with the Mosaic Law. He seeks to uphold it, and he teaches his followers to uphold it.
Fulsome: Jesus teaches that all the Law must be kept. As Matthew 5 begins to elucidate, every commandment matters—large and small, exterior and interior, ethical and ritual. The Law is to be interpreted holistically and harmoniously; it is addressed to the whole person, and the whole community; and no part of it is to be ignored. To fulfill the Law does not mean to bring it to an end. It means to fill it up to the fullest, to keep it in the most fulsome way.
Morally: The Law has a telos, a purpose, an end: individual moral formation and communal-social transformation. The Law envisions a holy and virtuous people following a holy and virtuous way of life that grows out of a covenantal relationship with a holy and perfect God. Every provision of the Law is oriented toward its moral telos. For Jesus, lawkeeping isn’t an end in itself. It is indelibly connected to the Law’s larger moral-formational agenda.
In future essays, I’ll continue to explore how Morally Fulsome Lawkeeping characterizes Jesus’s thought and helps us understand his teaching, debates, and legal discourse.
Even if one were to read Jesus’s dialogue with Satan in Matthew 4 as a kind of legal discourse, it would be fully consistent with the MFL model.