Pastor Timothy Keller defines legalism as more than the conscious belief that we can be saved by works. He describes it as a web of attitudes of heart and character: “It is the thought that God’s love for us is conditioned
on something we can be or do.” The opposite but equally destructive error is to think that we can ignore God’s law, “since God loves me regardless of my record, he doesn’t mind how morally or immorally I live.”
If attempting to keep the law and ignoring the law are both equally wrong, what else can we do? The Bible speaks of a third way. It is called “the law of the Spirit” (Rom. 8:2). Our own desire is not enough when it comes to God’s law (Rom. 7:16–18). Even when we intend to keep God’s law, we fall short due to indwelling sin.
The law itself is good and given by God, but it fails to make us good. It pointed out the sinfulness of humanity, but it did not provide salvation from that sin. What we need is a law that works from within that is stronger than our sinful nature. This is the work of the Holy Spirit. By the power of God’s indwelling Spirit we can say “no” to the impulses of our sinful nature and “yes” to righteousness.
Legalism leads only to moralism. This is a dead-end street paved with good intentions; its destination is failure and hypocrisy. Rules will not make us good. Only the ministry of God’s Spirit can accomplish that. The Holy Spirit enables us to put to death the misdeeds of the body (Rom. 8:13).
Christ’s work on the cross saves us from the penalty of sin. The indwelling Holy Spirit enables us to overcome the power of sin and empowers us to be righteous by practice as well as by position.