The word “legalism” does not occur in the Bible. But it comes from the word “legal,” which relates to “law,” and the Bible has lots to say about law. Legalism is a certain attitude toward God’s law. Or, more generally, toward commandments and rules.
Here is legalism: “Israel, pursuing a law of righteousness, did not arrive at that law. Why? Because they did not pursue it by faith, but as though it were by works” (Romans 9:31-32). The essence of legalism is when faith is not the engine of obedience.
Note well: legalism is not simply the pursuit of the law. It is pursuing the law in the wrong way—with some other engine than faith. The law of God should be pursued. The Son of God “condemned sin in the flesh, in order that the requirement of the law might be fulfilled in us, who do not walk according to the flesh, but according to the Spirit” (Romans 8:4). We should seek to fulfill the law—by the Spirit. Let’s call this good pursuit the “obedience of faith.”
So legalism is the pursuit of the law with some other engine than faith, on some other steam than the Spirit. What is the engine of legalism? Paul calls it “works” (Romans 9:32) and he calls the fuel of this engine “flesh” (Galatians 3:3). “Works” is the opposite of “faith” and “flesh” is the opposite of “Spirit.” So legalism is not whether you strive to obey the commands of God, but which engine and which fuel you run on.
Thus the power of legalism comes from ourselves (flesh). This is crucial because the aim of legalism is to trade with God value for value. And so the engine of works must have something self-wrought to offer God in the deal. “To the one who works, his wage is not reckoned as a favor but as what is due” (Romans 4:4). Legalism deals in debt-payments and magnifies its worth to God.
But the power of the “obedience of faith” does not come from ourselves but from God (the Spirit). The aim of the obedience of faith is to receive everything from God as a free gift of grace. And so the engine of faith must have nothing self-wrought in its dealing with God. “By the grace of God I am what I am … I labored harder than any of them, yet not I, but the grace of God with me” (1 Corinthians 15:10). The obedience of faith deals in beneficiary delights and magnifies the grace of God.
Implications for Prayer and Bible Reading
Discipline is not legalism. Hard work is not legalism. Acting against carnal impulses is not legalism. They may be. But they may also be the torque of the engine of faith running on the fuel of the Spirit to the glory of the grace of God in a self-centered and undisciplined world.
In the strength that God supplies that God may get the glory (1 Peter 4:11),