What is sin? Perhaps it is more appropriate to ask, why do we sin? The answer should help us better understand our behavior and how to overcome it.

The natural laws of physics will help us see the spiritual concept more clearly. Physics teaches that, generally, everything works in an orderly way, according to laws, and all causes have effects. The sun rises and sets day after day, caused by the earth's rotation. One effect is what we call day and night.

A more complex example would be something we experience daily. The forces of gravity and our weight putting a downward force on matter—say, a floor—create the effect of that material pushing back. Different materials possess distinct characteristics and thus push back differently. Thus, we do not fall through a floor unless its molecular integrity is compromised or its structure prohibits such an effect. In layman's terms, rock or wood pushes back stronger than water or sand because of their molecular densities. So, we can stand on a rock but sink in water.

Although we may not completely understand the principles behind these things, God has established an invisible law of cause and effect. More importantly, this law exists within both the physical and spiritual worlds, and we must deal with it on both levels. Spiritually, this law of cause and effect plays a significant part in overcoming.

Sin is more spiritual than it is physical. We know that sin is the transgression or breaking of the law of God (I John 3:4). Is sin, then, a cause or an effect? If it is an effect, what causes sin?

Genesis 4:2-7 tells the story of how Cain, jealous of his brother Abel's favor with God, killed him. Something God says to a furious Cain sheds light on this subject. Notice verse 6, "So the LORD said to Cain, ‘Why are you angry? And why has your countenance fallen?'" God then tells him that if he does well, He will accept him (verse 7).

Why did God say this to him? Cain's contention centered on the brothers' offerings to God, that God accepted Abel's but rejected Cain's (verses 3-4). Abel gave of the firstlings of the flock, while Cain presented fruit of the ground. A deeper dive would reveal what types of offerings they gave and what they mean.

In summary, Cain's offering of the fruit of the ground represents his works—showing that he tilled the ground, planted the seed, gave the plants water, pulled the weeds, and nurtured them until they bore fruit. It is an offering of works, which he thought God wanted. It is based fully on what he thought was right in his own eyes, not on revering God. The offering shows Cain tried to worship God his way, reflecting that he controlled his own life.

By contrast, Abel's offering was the best lamb from his flock. God provided it, and Abel gave the most desirous part to Him, never considering keeping it for himself. Abel respected God enough to give Him, not something that he did, but a product of what God had provided. His offering reflects his reliance on God and gratitude for His providence.

In other words, the brothers' offerings directly related to what was in their hearts. This fact reveals why verses 5-6 are vital to understanding how sin develops. Recall that Cain was angry, and his countenance fell. This sequence shows that his sin began with anger and a fallen countenance. But what does this mean?

Cain's fallen countenance describes his emotions portrayed for all to see on his face, revealing his lack of acceptance of God's judgment. In a few words, the description illustrates his feeling of unworthiness and his desire for approval. These emotions—his anger, his shame, and his craving for approval—caused him to kill his brother.

At this point, God's words to Cain in verse 7 make sense. He explains that one's mental state needs to be controlled because it either leads to good behavior or bad—sin. Breaking God's law is an effect of what is in an individual's heart or mind (see Matthew 15:10-11, 15-20).

If we examine ourselves, we will likely find that we, just like Cain, desire acceptance. For instance, when we lie, are we not trying to make ourselves sound good and so be accepted by others? When we surrender to peer pressure, is it not to receive the approval of certain people?

This mental state is not limited to humans. Ezekiel 28:14-16 records how sin entered the angelic realm. The covering cherub who became Satan was perfect in his ways until iniquity was found in him. He then filled his heart with self-centered emotions, desires, and perspectives, and he sinned (see also Isaiah 14:13-14).

In this passage, God divides Satan's sinfulness into two categories. The "iniquity" He found in him is evil or wickedness, while the "sin" he committed is wrongdoing, willfully acting against God's will. His wicked mind—or mental state—is the cause, and the subsequent sinful action is the effect. His iniquity was in his thoughts, desires, and pride, which made him intensely hate God and His purpose! Thus was created in him the foundation for sin. It even made him want to be worshipped ("I will be like the Most High"). Like Cain, he wanted to be accepted and more. This progression of sin matches what the apostle James writes in James 1:14-15: Our desires and conceits are the causes of sin.

We blind ourselves to the reality of sin. Sin is nothing more than the effect of our carnal desires, thoughts, beliefs, selfish plans, and pride. We sin because we do not respect God enough to offer ourselves as a living sacrifice to Him in faith as Abel did (Romans 12:1; Hebrews 11:4). Too often, desiring acceptance, we would rather try to do things ourselves or try to worship Him in our own way as Cain did.

The upshot—and futility—of all this is that we cannot receive the acceptance we need from ourselves or any other human! It must come from God. At the end, when Christ's judgment is final, if we have lived righteously, He will say, "Well done, good and faithful servant" (Matthew 25:21-23). We can see this as fulfilling God's words to Cain in Genesis 4: "If you do well, will you not be accepted?" Yes, with God's own praise!

God wants to accept us, as proven by what Jesus Christ did. He sacrificed everything, including His status as a God-being, for the Father's purpose and in His love for us. The Father noted and praised Him for His sacrificial attitude, saying, "This is My beloved Son, in whom I am well pleased" (Matthew 3:17; 17:5; Mark 1:11; 9:7; Luke 3:22; 9:35; I Peter 1:17). In his offering, Abel's attitude was an early type of Christ's humble sacrifice. If we follow His steps as Abel did, will God not also be pleased with us and accept us?

To be accepted, we must overcome the cause of our sins. The second example from physics comes into play here. Like pushing against gravity to walk, we must push back against the pressures of Satan and this world. We do this by controlling our thoughts, beliefs, desires, and pride. We prevail against sin by cutting off the effects of our selfishness at their roots.

In short, we forestall sin by doing what God advises in Genesis 4:7: "And if you do not do well, sin lies at the door. And its desire is for, but you should rule over it" (emphasis ours). We must become masters over our hearts and minds. We can do so through faith in God and what He teaches, through a desire for Him and what He promises, and through humble self-sacrifice and imitation of Christ.

The apostle John warns us against Cain's attitude in I John 3:12, commanding us instead to "love one another" (verse 11). The Cain-like proud and selfish mental state creates wickedness and spurs separation from our brethren and ultimately from God. The way to receive God's acceptance is to rid ourselves of the cause of our sins, the evils that lie within. The effects will be righteousness, peace and unity with Him, and overflowing gratitude to the God who provides us life and blessing.