This third session in the Catechism series turns to a deeply important question: how a good and merciful God provides a Redeemer. Yet before we can truly understand salvation, we must first understand sin. This is not because Christianity is preoccupied with guilt or negativity, but because the Bible speaks honestly about reality. While the world may grow accustomed to sin or redefine it according to changing standards, this does not alter how God defines it.
One of the most common distortions of sin is measuring it against other people, cultural norms, or human laws. In such a framework, sin becomes relative—less serious if others are worse, or acceptable if society permits it. Scripture rejects this entirely. Sin is defined as falling short of the glory of God. It is like an archer missing the center of a target—not merely being slightly off, but failing to meet the perfect standard of God’s holiness. Sin, therefore, is not relative but absolute.
Another misunderstanding is treating sin as merely a mistake, weakness, or imperfection. The Bible presents a far more serious diagnosis. Sin is not only something we do; it is something we are. It is a condition we are born into, shaping our thoughts, desires, relationships, and even our perception of God. At its core, sin reflects a deep-seated hostility toward God, leading us to live independently of Him and to seek solutions to life’s problems without reference to Him.
To understand why this is so, we must return to the beginning. God created humanity good, upright, and in fellowship with Him. However, mankind was created as a unified race, connected through a natural and biological lineage. Adam, therefore, was not merely an individual but the representative head of humanity. When he disobeyed God, sin entered the world through him, and its effects spread to all his descendants. As Scripture teaches, through the disobedience of one man, many were made sinners. This means that humanity did not simply imitate Adam’s sin; rather, we participated in it through his representation. As a result, we are by nature estranged from God, inclined toward self-reliance, and subject to His judgment. Sin feels natural to us not because it is right, but because we are born sinners. We do not become sinners by sinning; we sin because we are sinners.
The Catechism defines sin as any lack of conformity to, or transgression of, the law of God. To transgress is to cross a boundary that God has set. It is not accidental but deliberate, a willful stepping over the line of His command. Whether through explicit commandments in Scripture or the moral law written on our hearts, we knowingly rebel against God. This is what makes sin so serious—it is not merely failure, but defiance.
This is clearly seen in the first sin of Adam and Eve. The act of eating the forbidden fruit was not inherently sinful because of the fruit itself, but because it violated God’s command. Even before the physical act, sin had already taken root in the heart. Doubt in God’s goodness, distrust in His word, and the desire for autonomy led to deliberate disobedience. The tree in the garden was not placed there to tempt humanity, but to represent a choice: to live under God’s rule in trust and obedience, or to seek independence by defining good and evil for oneself. Adam and Eve chose the latter, and in doing so, brought sin into the human experience.
This leads to the doctrine often called original sin, which teaches that all humanity fell in Adam’s first transgression. Because Adam stood as our representative, his sin is counted as ours. All who descend from him by ordinary generation inherit both the guilt and the corruption of his sin. This explains why every person is born in a fallen state, already subject to death and judgment, even before committing personal acts of sin. Scripture affirms that in Adam all die, pointing to a legal and covenantal reality in which humanity shares in his fall.
At first, this idea may seem unfair. Why should one man represent us all? Yet Adam was created upright, with every advantage to obey God—advantages we no longer possess. More importantly, this principle of representation is not only the basis of our condemnation, but also of our salvation. Just as we are made sinners through Adam’s disobedience, we are made righteous through the obedience of another representative, Jesus Christ. If we reject representation in Adam, we undermine the very foundation of redemption in Christ. God’s wisdom is seen in this structure, where one stands for many, making both judgment and salvation possible.
The fallen condition of humanity consists of both guilt and corruption. We bear the guilt of Adam’s sin, meaning we stand legally condemned before God. At the same time, our nature is corrupted—we have lost original righteousness and are inclined toward evil. This corruption affects every part of our being, so that sin flows not merely from external circumstances but from within the heart. As Jesus taught, evil thoughts and actions arise from the inner person. This is what theologians mean by total depravity: not that every person is as sinful as possible, but that every part of our nature is affected by sin, leaving us unable to produce true spiritual good on our own.
The result of this fallen state is misery. Humanity has lost communion with God and lives under His righteous wrath and curse. This misery is expressed in various ways: the hardships and sufferings of life, physical death, and ultimately eternal separation from God. Scripture speaks of three kinds of death: physical death, where the body and soul are separated; spiritual death, where the soul is alienated from God; and the second death, which is eternal judgment. Hell is not annihilation, but a state of conscious and everlasting punishment. Though this is a sobering reality, it is meant to awaken us—to make us vigilant against sin and urgent in proclaiming the gospel, recognizing the immense cost of salvation.
Yet the story does not end in judgment. God did not leave humanity to perish. Out of His own good pleasure, from all eternity, He chose to save a people for Himself. This choice, often called election, is not based on human merit or foreseen goodness, but entirely on God’s sovereign grace. Because God is perfectly good, His will and pleasure are always righteous. To say that He saves according to His good pleasure is not to accuse Him of arbitrariness, but to affirm His perfect wisdom and goodness.
In His grace, God established a covenant of grace, a plan to deliver His people from the estate of sin and misery and bring them into salvation through a Redeemer. This Redeemer is Jesus Christ, who fulfills what Adam failed to do. Where Adam disobeyed, Christ obeyed. Where Adam brought condemnation, Christ brings righteousness and life. Through Him, the guilt of sin is removed, the power of sin is broken, and the hope of eternal life is secured.
Understanding sin in its full weight is essential because it magnifies the glory of grace. Only when we see how deep the problem runs can we appreciate how great the solution truly is. The gospel is not a minor adjustment to human life, but a complete rescue from sin, judgment, and death, accomplished entirely by God’s mercy through Jesus Christ.
