Why Do We Sin?

We are not sinners merely because we sin; we sin because we are sinners.

We must be delivered from both original sin and actual sin. The Holy Spirit removes the corruption of our natures by breaking the power and dominion of sin. Christ removes the imputation of Adam’s sin through the imputation of Christ’s righteousness. This restores us to a right relation to the Father through faith. The Holy Spirit also removes actual sin from our lives by bringing repentance and conforming us to God’s law through Christ. All we need to inherit original sin is birth. In order to inherit the kingdom of God, we need new birth.


Few people understand the extent of sin and the doctrine of total depravity. Paul summarizes our sinful condition by combining several Old Testament texts:

“None is righteous, no, not one; no one understands; no one seeks for God. All have turned aside; together they have become worthless; no one does good, not even one.” “Their throat is an open grave; they use their tongues to deceive.” “The venom of asps is under their lips.” “Their mouth is full of curses and bitterness.” “Their feet are swift to shed blood; in their paths are ruin and misery, and the way of peace they have not known.” “There is no fear of God before their eyes.” (Rom. 3:10–18)

This is what it looks like to be “dead” in trespasses and sins (Eph. 2:1). All sin is rooted in failing to glorify God as “the true God and our God” (Westminster Shorter Catechism 47). It is bad to be sinners before a holy God, but it is even worse to be unaware of who we are and why we need Christ to save us.

However, the Bible not only teaches that we are born dead in sin, that we are averse to living for God’s glory, and that we are inclined to evil, but it also teaches that all humanity died in Adam because all sinned in Adam (Rom. 5:12, 15, 191 Cor. 15:22). This is what the church has called original sin. In order to understand this truth, I will show what original sin means and how it leads to all actual sins that we commit against God’s law. I will use Westminster Larger Catechism questions 24–26 to help us think through Scripture on the nature of sin and original sin. These issues are important because without understanding the nature, depths, and extent of our ruin, we cannot understand the glory of God’s remedy for sin in Christ.


Before considering original sin, it is important to ask what sin is. For some people, sin means “brokenness” or “poor choices.” This misses the mark, focusing on the effects of sin on our lives rather than on the nature of sin itself. The Apostle John wrote, “Sin is lawlessness” (1 John 3:4). While we can understand “brokenness” or “poor choices” without referring to God, we cannot understand sin without God and His law. It is not stones and trees or even animals that break God’s law but human and angelic beings.

We break God’s law negatively and positively. Negatively, sin is “want of conformity unto” the law. The First Catechism defines “want of conformity” as “not being or doing what God requires.”2 We should love God supremely, and we should love Him while we love others and above others. Failing to be worshipers and servants of the true God, trusting in Christ as our Savior, and depending on the Spirit to trust and obey God makes everything we think, do, or say sinful by definition.

Positively, we break God’s law by transgressing it. As sinners, we do not simply stand still. We actively cross lines that God has put in place. God commands us to have no other gods before Him, even while we create a pluralistic society in which all religious ideas are equal. God says not to murder, and we slander others, curse them, or harbor anger and bitterness toward them in our hearts (Matt. 5:21–22James 3:9). God tells children to obey their parents in the Lord (Eph. 6:1), and the curse of sin shows itself in disobedience to parents (Rom. 1:30). These principles apply to “any law of God.” Without God, sin evaporates into nonexistence. Sin is both great and bad because the triune God is so great and good (Ps. 119:68).


In light of this definition of sin, it may surprise some people that the Westminster Larger Catechism begins with “the guilt of Adam’s first sin.” This is part of original sin. Adam represented humanity in what theologians have called the covenant of works. While I cannot explore this idea here, it means that just as Christ represents His people in the covenant of grace, so Adam represented human beings in a different covenant. This means that just as Christ acted in our place, so did Adam. Paul says that “sin came into the world through one man, and death through sin, and so death spread to all men because all sinned” (Rom. 5:12). Drawing the parallel between Adam and Christ, he adds, “For as by the one man’s disobedience the many were made sinners, so by the one man’s obedience the many will be made righteous” (v. 19). This involves imputation, which means that Adam’s sin in eating the fruit of the forbidden tree was counted to his descendants in the same way that Christ’s obedience is counted to those who trust in Him. All who are in Adam die, and all who are in Christ will be made alive (1 Cor. 15:22). We cannot understand the imputed righteousness of Christ unless we understand that it is God’s remedy to the imputed guilt of Adam.

  1. “Sin is any want of conformity unto, or transgression of, any law of God, given as a rule the reasonable creature” (Westminster Larger Catechism 24). ↩︎
  2. Question 30. This document can be found at https://www.opc.org/cce/FirstCatechism.html↩︎
  3. “The sinfulness of that estate whereinto man fell, consisteth in the guilt of Adam’s first sin, the want of that righteousness wherein he was created, and the corruption of his nature, whereby he is utterly indisposed, disabled, and made opposite unto all that is spiritually good, and wholly inclined to all evil, and that continually; which is commonly called original sin, and from which do proceed all actual transgressions” (WLC 25). ↩︎

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