What Is Sin?

Throughout this course we’ve seen that God explains what sin is. But His Word has more to say on the matter than what we’ve already encountered. We begin this lesson by examining the aspects of sin most commonly referred to in the Bible. At the same time we will learn why we sin so we can better understand the necessity of the conversion process. We will then proceed to the other aspects of repentance, baptism and conversion.

How does the Bible define sin in its most direct form?

“Whoever commits sin also commits lawlessness, and sin is lawlessness” (1 John 3:4).

God’s law defines the difference between right and wrong, between sin and righteousness. As Paul explained, “By the law is the knowledge of sin” (Romans 3:20).

What is the core of God’s law?

“And [God] wrote on the tablets . . . the Ten Commandments, which the Lord had spoken to you in the mountain from the midst of the fire in the day of the assembly; and the Lord gave them to [Moses]” (Deuteronomy 10:4).

All of Scripture’s commands and other laws are based on the principles contained in the Ten Commandments—and the Ten Commandments are based on the two great commandments of love toward God and neighbor (Matthew 22:37-40; compare 1 John 4:8, 16; Romans 13:9-10).

Sin is behaving or thinking in a manner contrary to showing love to God and to our neighbor. It brings harm to others as well as ourselves. It is especially destructive to our relationships with each other and God.

(For a fuller explanation of the damage caused by breaking God’s commandments, and the benefits we reap from obeying them, be sure to request your free copy of our study guide The Ten Commandments.)

What must we do first to be converted?

“. . . If a wicked man turns from all his sins which he has committed, keeps all My statutes, and does what is lawful and right, he shall surely live . . .” (Ezekiel 18:21).

To be converted—to turn away from sin and receive God’s forgiveness and the Holy Spirit—we must stop transgressing His laws and start developing habits of righteousness through obedience to them. God declares: “Again, when I say to the wicked, ‘You shall surely die,’ if he turns from his sin and does what is lawful and right, if the wicked restores the pledge, gives back what he has stolen, and walks in the statutes of life without committing iniquity, he shall surely live; he shall not die. None of his sins which he has committed shall be remembered against him; he has done what is lawful and right; he shall surely live” (Ezekiel 33:14-16).

How widespread is sin?

“As it is written: ‘There is none righteous, no, not one; there is none who understands; there is none who seeks after God. They have all turned aside; they have together become unprofitable; there is none who does good, no, not one’” (Romans 3:10-12; compare verse 23).

The Bible tells us that we all have yielded to the lusts and selfishness of corrupted human nature and have violated God’s laws.

Let’s consider how the Bible portrays various aspects of sin and, at the same time, explains why we sin.

Are some sins more easily recognized than others?

“Now the works of the flesh [corrupt human nature] are evident, which are adultery, fornication, uncleanness, lewdness, idolatry, sorcery, hatred, contentions, jealousies, outbursts of wrath, selfish ambitions, dissensions, heresies, envy, murders, drunkenness, revelries, and the like; of which I tell you beforehand, just as I also told you in time past, that those who practice such things will not inherit the kingdom of God” (Galatians 5:19-21).

Almost everyone understands that outrageously aggressive, hostile and self-indulgent behavior is harmful. But not everyone clearly sees the source of such behavior. Therefore some aspects of sin are not as obvious as those Paul described to the Galatians.

Where does sin begin?

“But those things which proceed out of the mouth come forth from the heart, and they defile the man. For out of the heart proceed evil thoughts . . .” (Matthew 15:18-19).

“But each one is tempted when he is drawn away by his own desires and enticed. Then, when desire has conceived, it gives birth to sin; and sin, when it is full-grown, brings forth death” (James 1:14-15).

Sin begins in our minds. It starts with harmful thoughts, desires and attitudes. Paul tells us that “we all once conducted ourselves in the lusts of our flesh, fulfilling the desires of the flesh and of the mind, and were by nature children of wrath, just as the others” (Ephesians 2:3; compare Romans 1:28-32; Galatians 5:24; Colossians 3:5-9).

Does Jesus give clear examples of such sins?

“But I say to you that whoever is angry with his brother without a cause shall be in danger of the judgment. And whoever says to his brother, ‘Raca [or empty-headed]!’ shall be in danger of the council. But whoever says, ‘You fool!’ shall be in danger of hell fire” (Matthew 5:22).

“But I say to you that whoever looks at a woman to lust for her has already committed adultery with her in his heart” (verse 28).

Disobedience to God’s laws always begins in the mind. Jesus cited the evils of unjust anger and extramarital lust to illustrate this principle. The apostle John further explained that “whoever hates his brother is a murderer” (1 John 3:15). The apostle Peter likewise understood that sin is the product of corrupted thinking. When rebuking Simon the Sorcerer, Peter advised him, “Repent therefore of this your wickedness, and pray God if perhaps the thought of your heart may be forgiven you” (Acts 8:22; compare Psalm 81:11-13).

Is it a sin for us to defile our conscience?

“Now the purpose of the commandment is love from a pure heart, from a good conscience, and from sincere faith” (1 Timothy 1:5).

“. . . Whatever is not from faith is sin” (Romans 14:23).

Our conscience is our sense of right and wrong, whether correct or not. When we violate our conscience, we are doing something we think we shouldn’t, and thus are compromising with what we think is wrong. Paul says that this, too, is sin.  

No one is born automatically knowing right from wrong. As we have already seen in this Bible study course, a proper understanding of right and wrong comes from knowing God’s law. That knowledge becomes a part of our conscience. If we act contrary to that knowledge, in letter or in spirit, we sin. We also sin even without right knowledge when we do or think something we believe may be wrong.

The apostle Paul further warned: “Now the Spirit expressly says that in latter times some will depart from the faith, giving heed to deceiving spirits and doctrines of demons, speaking lies in hypocrisy, having their own conscience seared with a hot iron” (1 Timothy 4:1-2). If we continue to sin when we know better, we run the risk of “searing” our conscience so we become less sensitive to sin and thus become hardened toward God.

Is it possible to see ourselves as more righteous than we are?

“Also He [Jesus] spoke this parable to some who trusted in themselves that they were righteous, and despised others” (Luke 18:9).

In the parable that begins with the next verse in Luke’s Gospel, Jesus illustrates how easy it is for a person to consider himself righteous when he’s not: “Two men went up to the temple to pray, one a Pharisee and the other a tax collector. The Pharisee stood and prayed thus with himself, ‘God, I thank You that I am not like other men—extortioners, unjust, adulterers, or even as this tax collector. I fast twice a week; I give tithes of all that I possess.’ And the tax collector, standing afar off, would not so much as raise his eyes to heaven, but beat his breast, saying, ‘God, be merciful to me a sinner!’” (verses 10-13).

The Pharisee, a member of a respected religious group, observed the outward requirements of the law. He appeared righteous to others, but he entirely missed the overall purpose of so many of God’s laws—loving and respecting one’s fellow man. In his heart he disdained other people and failed to see and confess his own sin.

In contrast, the tax collector, a member of a despised profession that was notorious for cheating people, could see that he had been sinning. He came to God repentant, seeking His merciful forgiveness so he could begin his life anew. Jesus concluded His parable by saying, “I tell you, this man went down to his house justified rather than the other; for everyone who exalts himself will be humbled, and he who humbles himself will be exalted” (verse 14). Only those who humble themselves enough to recognize their sinful attitudes, desires and motives can find true repentance. Those who remain righteous in their own eyes remain spiritually blind.