What does Mark 12:31 mean?When a scribe challenges Jesus to choose the greatest commandment in the Mosaic law, Jesus answers with the beginning of the Shema from Deuteronomy 6:4–5: "Hear, O Israel: The LORD our God, the LORD is one. You shall love the LORD your God with all your heart and with all your soul and with all your might." This part of the Mosaic law encompasses the first four of the Ten Commandments and every other part of the Law that describes how the Israelites are to respond to God.
Jesus continues His answer from Leviticus 19:18. "Love God" is the basis for all the laws, including loving others: we cannot know how to properly love others if we don't first love God. "Love others" fulfills all parts of the Law which don't relate directly to God, including the last six of the Ten Commandments. When loving others, we don't steal from them, we don't murder them, we don't lie about them (Exodus 20:12–17). Going further, we care for people in need (Exodus 22:21–27), we protect vulnerable women (Exodus 21:7–11), and we don't kidnap people and sell them into slavery (Exodus 21:16).
The passage on how to love others in Leviticus identifies the "others" as "your neighbor" (Leviticus 19:13, 15), "your people" (Leviticus 19:16), "your brother" (Leviticus 19:17), and "the sons of your own people" (Leviticus 19:18). By this time, however, Jesus has already turned the concept of "your neighbor" on its ear. In the parable of the good Samaritan, Jesus explains that anyone who is near you and in need is your responsibility (Luke 10:25–37). Matthew 5:43 extends the meaning even further to include our enemies.
The scribe initially asks Jesus what the "most important" law is (Mark 12:28). That term is taken from the Greek root word prōtos, which means "foundational or principal," implying the law from which all others come. Jesus responds by also describing this as the "greatest" law. "Greater" is from the Greek root word megas. In this case, it refers to a law that is greater in scope and degree than any other. These laws are the basis for all the Mosaic law as well as all the prophets (Matthew 22:40). Jesus' three-part law—know God, love God, love others—isn't just the first law we need to consider, it encompasses everything God wants us to do.