Most imagine Satan as the ultimate rebel—an outlaw who delights in breaking rules. But Scripture reveals a far more insidious strategy: Satan is, at his core, a legalist. His chief weapon is not open lawlessness, but the perversion of God’s own Law to entrap humanity in self-righteousness, condemnation, and alienation from God. This is not a secondary issue; it strikes at the very heart of the gospel, justification, and our inheritance as sons.
The Origin of Legalism: Satan’s Injection of Sin
In the garden, Satan did not simply tempt Adam and Eve to disobey. He injected into humanity the knowledge of good and evil—a foreign element that is nothing less than his own nature (Genesis 3:1-7). This act was not a gift of discernment, but a poison that corrupted the conscience, causing mankind to shrink back from God in shame and fear. The result was catastrophic: sin became part of humanity, and with it, the relentless drive to justify ourselves by our own knowledge and effort.
Why did Satan do this? Because he coveted the dominion God gave to man. Offended that God would exalt “clay” over the works of His hands, Satan sought to usurp that authority and become the god of this world. His strategy is to force God’s hand—to demand judgment on man, and to accuse God Himself of lawlessness if He dares to justify sinners by faith.
Sin’s Nature: Deception Through the Law
Romans 7 exposes the true character of sin as the nature of Satan. Sin is not merely wrongdoing; it is an active, deceiving power that takes God’s holy Law and twists it into a tool for death (Romans 7:8-11). The Law, in God’s hand, is meant to expose and condemn sin—to reveal its true nature and drive us to Christ. But under Satan’s influence, sin deceives us into thinking we can keep the Law and earn righteousness.
This is the heart of legalism: the belief that we can be justified by our own works. But the result is always the same—condemnation, weakness, and death. The Law becomes a ministry of condemnation, not because it is evil, but because sin uses it to blind us to our need for Christ (2 Corinthians 3:7, 14-16). When we pursue the Law instead of Christ, it becomes a veil, obscuring the glory of the gospel and keeping us in bondage.
The Accuser’s War Against Grace
Satan is relentless in his opposition to justification by faith. He stands before God, day and night, accusing both God and the saints (Revelation 12:10). He charges God with lawlessness for justifying the ungodly, insisting that only those who keep the Law deserve to be called children and heirs. He is the father of every legalistic Pharisee and the spirit behind Cain, who hated Abel for offering a blood sacrifice that pointed to faith in Christ (Genesis 4:3-8).
This is not a mere theological debate. If you accept Satan’s logic—if you believe righteousness comes by works—you forfeit everything: justification, sonship, and inheritance. The gospel is emptied of its power, and you are left condemned, striving endlessly under a burden you can never lift.
God’s Answer: Justification by Faith Alone
But God has not left us in this trap. In Christ, He has provided a righteousness that is entirely a gift—secured by the blood of Jesus, received by faith alone (Romans 3:26; Ephesians 2:8-9). God is both just and the justifier of those who believe in Jesus. He does not compromise His righteousness; He manifests it in the propitiation of Christ.
The Law’s true purpose is fulfilled: it exposes sin, drives us to despair of self, and points us to the only ground where Satan’s accusations are silenced—the finished work of Christ. When you stand on this ground, you are not merely forgiven; you are declared righteous, made a child and heir, and set free from the tyranny of legalism.
What Is Lost If You Accept Legalism?
If you embrace the legalist’s gospel, you lose everything that matters. You lose the assurance of justification. You lose your standing as a son and heir. You forfeit the rest and freedom that come only from Christ’s finished work. You remain under the veil, blinded, condemned, and alienated from the God who justifies the ungodly. This is not a peripheral error—it is a denial of the gospel itself.
The Only Safe Ground
Do not be deceived: Satan’s most effective weapon is not open rebellion, but the subtle seduction of self-righteousness. Reject every demand to justify yourself by law or works. Stand boldly on the blood of Christ alone. Here, and here only, are you complete, righteous, and untouchable by the accuser. This is the ground of your inheritance, your sonship, and your eternal security.
