Today, sin is treated dismissively, even as a joke. Even many Christians are ambivalent about it. They believe that because Jesus died for our sins, sin is irrelevant once you accept His sacrifice. But what does the Bible say?

God’s inspired definition is this: “[S]in is the transgression of the law” (1 John 3:4).

The Apostle Paul would not have known what sin is, except by the law. Which law? The law that says, “Thou shalt not covet” (Romans 7:7): the Ten Commandments. Paul described this law as being “holy, and just, and good” (verse 12). King David called it perfect, sure, right and pure, more valuable than fine gold (Psalm 19:7-11).

God’s law codifies the way God thinks and acts. It is an expression of His character and nature. God is love (1 John 4:8), and His law can be summed up in that one word: love. Jesus said the law is further defined in two great commandments: love to God and love to neighbor (Matthew 22:36-40). The same law is further divided into 10 points by the Ten Commandments, the first four of which tell us how to love God, the last six of which tell us how to love neighbor (Exodus 20).

God’s law of love is the perfect way of life. All suffering, unhappiness, misery and death have come solely from breaking it.

“If ye fulfil the royal law according to the scripture, Thou shalt love thy neighbour as thyself, ye do well” (James 2:8). Love is the fulfilling of the law (Romans 13:8, 10)—not our human-level love, but “the love of God [which] is shed abroad in our hearts by the Holy [Spirit]” (Romans 5:5).

If we fulfill this royal law, we do well—but if not, we commit sin (James 2:9). If we keep the whole law (the principle of love to neighbor) yet break one point of it, we are guilty of all (verses 10-11). (Notice: The points of the law James describes are, do not commit adultery, do not kill—the Ten Commandments.)

Jesus Christ was the ultimate example of perfect obedience to the law. Most Christians believe that Jesus came to Earth to abolish the Ten Commandments. Yet He clearly stated, “Think not that I am come to destroy the law, or the prophets: I am not come to destroy, but to fulfil” (Matthew 5:17). Jesus came to “magnify the law, and make it honourable” (Isaiah 42:21). When we put a spiritual “magnifying glass” on the Ten Commandments, they are enlarged in spirit and principle into many more points. And in the larger view, the entire Bible is a magnification of God’s law. The law is the basis of all Scripture. It defines a way of life: God’s way to happiness, joy and eternal life.

Truly fulfilling the Ten Commandments requires keeping not just the letter of the law, but also the spirit. Christ gave two examples illustrating this point. First: “Ye have heard that it was said by them of old time, Thou shalt not kill; and whosoever shall kill shall be in danger of the judgment: But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment …” (Matthew 5:21-22). He quoted the Sixth Commandment, which forbids murder (Exodus 20:13). He affirmed that maliciously ending a human life is sin. Then He magnified that law, showing that the spirit of murder, including hatred, is also sin.

Second: Christ addressed the Seventh Commandment, saying, “Ye have heard that it was said by them of old time, Thou shalt not commit adultery: But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart” (Matthew 5:27-28). Christ upheld God’s law forbidding adultery, which includes premarital sexual activity as well as infidelity within marriage. Then He magnified it, showing that even a lustful gaze breaks the spirit of that commandment. These examples show that sin against God’s spiritual law begins in the mind and must be stopped immediately (James 1:14-15).

In principle, sin is anything other than God’s outflowing law of love. At the root of all sin is vanity—loving self more than loving God or fellow man. Its author is Lucifer, whose heart was lifted up because of his beauty (Ezekiel 28:17). It is manifest in attitudes of self-centeredness, self-exaltation, desire to be beautiful, coveting, desire to get and take, jealousy and envy, competition, resentment and rebellion against authority, violence and war. These are the principles of spiritual sin.

To repent of sin means to turn from sin—to quit sinning. And the way to do so is to begin keeping God’s commandments—all of them, for if you break only one, you incur the penalty of sin, which is not eternal life in hell, but death (Romans 6:23)—eternal death.

Thankfully, the sacrifice of Jesus Christ pays that death penalty (Romans 5:6-10). Once someone repents, he or she is no longer doomed to eternal death. However, God still expects those He forgives to keep the Ten Commandments. “What shall we say then? Shall we continue in sin, that grace may abound? God forbid. How shall we, that are dead to sin, live any longer therein?” (Romans 6:1-2). It is now our responsibility to choose to slay sin—to choose not death, but life (Deuteronomy 30:19).