Legalism and antinomianism always end up looking the same.  The devil tricks us into thinking we’re correcting an error when we end up just committing the same one.  Reacting against legalism, the devil lures us with antinomianism, saying, “Don’t go that way, go this way instead!”  And then we just end up falling off the ditch in the other direction.

This is because we can’t live without law.  We must have principles that guide our lives and judge the appropriateness of actions.  The only question will ever be whether it’s man’s law or God’s.  So the legalist might begin by looking very concerned about God’s law, like the Pharisees, but condemned by the actual law of God, they reduce it merely to doable outward observances and add to it their own hedges and glosses, claiming to have great respect for the law but in fact teaching as law their own commandments.  Thus they have become antinomians, substituting their own law for God’s.  The teetotaler movement, for example, is both legalistic and antinomian- it imposes law-keeping on people, but it is not God’s law, but man’s.

The antinomian on the other hand might start looking like he has a great appreciation for God’s grace, resting in the fact that Christ has completely satisfied the demands of the law on their behalf.  But they ignore the purpose of this salvation, which is that we walk in good works in glory to God (Ephesians 2:8-10).  And then, because man cannot live without law, they invent other principles by which they justify themselves and judge others, whether it is political values, diet, money management or other things.  Some antinomians ironically become extremely judgmental whether or not you are preaching the gospel in exactly the way they think you should, talking about God’s law in exactly the way they think you should, or following exactly the liturgical formula that they prescribe.  Man cannot live without law, so having rejected the law of God as a normative guide for our lives, the antinomian inevitably substitutes his own law, and thus becomes a legalist.

It’s never a question of whether or not you will live by law.  It’s only a question of whether that law will be God’s law or one you make up.  That is the only real choice.  If we recognize that Christ has completely satisfied the demands of God’s law on our behalf, for the very purpose of conforming us to that law, then we will avoid either error.