The opposite of wrong isn’t always right. Sometimes it’s simply a different kind of wrong.
There are two dominant errors Christians fall into that can damage and destroy their integrity. You can think of them as two equally treacherous ditches on either side of the narrow way (Matthew 7:14).
On one side you have legalism. With strict rules that govern outward behavior, legalists don’t put much emphasis on integrity. It matters what you do—or moreover, what you don’t do—not why or how you do it.
In legalism, conformity takes the place of faithfulness. Your rigid adherence to the rules is what matters—not the attitude that undergirds your outward obedience or the true nature of your heart’s affections. Integrity is merely the measure of how consistently you follow the rules. It has nothing to do with the inner transforming work of the Spirit, or the mortification of the flesh (Romans 8:13).
Legalists also measure their own spiritual maturity by the flaws they can spot in others. Christ’s parable of the Pharisee and the tax collector in Luke 18 is a prime example. Scripture makes it clear the Pharisee prayed these words for his own benefit: “God, I thank You that I am not like other people: swindlers, unjust, adulterers, or even like this tax collector. I fast twice a week; I pay tithes of all that I get” (Luke 18:11-12).
Christ was born into a world ruled by the Pharisees’ heavy-handed legalism. They had reduced God’s law—along with its rich symbolism that pointed to the coming Messiah—to an oppressive list of prescriptions and prohibitions. The apostles knew firsthand the threat that legalism posed to the early church, and warned against succumbing to its influence. Paul exhorted the Galatians to withstand the pressures of the legalistic Judaizers, who attempted to add works to grace: “It was for freedom that Christ set us free; therefore keep standing firm and do not be subject again to a yoke of slavery” (Galatians 5:1).
One of the dangers of legalism is that it shortcuts the need for integrity. When godliness isn’t measured in holiness and maturity, but by how your life looks relative to others, there’s no need to discipline your heart and mind. Sins that no one else can see essentially don’t count, and you wind up living a hypocritical double life. Your outward behavior might look godly but it’s a worthless façade if your heart is still dominated by selfishness, lust, hatred, and pride. And if your godliness is just a façade, you can be sure it will eventually collapse and expose the hypocrisy within.
The opposite error of legalism’s spiritual pantomime is lawlessness. Just as legalism posed a threat to the early church, antinomianism—the belief that God’s law no longer applies to Christians—was a spiritual plague in the first-century church.
Paul wrote to the Ephesian church to encourage them to shed their sinful habits and live out the transformation God had already worked within: “For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand so that we would walk in them” (Ephesians 2:10). He hammered that same point in his letter to the Colossians:
Therefore if you have been raised up with Christ, keep seeking the things above, where Christ is, seated at the right hand of God. Set your mind on the things above, not on the things that are on earth. For you have died and your life is hidden with Christ in God. . . . Therefore consider the members of your earthly body as dead to immorality, impurity, passion, evil desire, and greed, which amounts to idolatry. For it is because of these things that the wrath of God will come upon the sons of disobedience, and in them you also once walked, when you were living in them. But now you also, put them all aside: anger, wrath, malice, slander, and abusive speech from your mouth. Do not lie to one another, since you laid aside the old self with its evil practices, and have put on the new self who is being renewed to a true knowledge according to the image of the One who created him. (Colossians 3:1-10)
He issued a similar reminder in Titus 2:11-12, “For the grace of God has appeared . . . instructing us to deny ungodliness and worldly desires and to live sensibly, righteously and godly in the present age.”
Despite these and other clear exhortations from Scripture, antinomianism still lives—and thrives—in corners of the church today.
We’ve dealt with the Hypergrace movement in the past (here and here)—in simple terms, it stresses Scripture’s indicative statements (for example, that we’ve been saved by grace—Ephesians 2:8) while downplaying its imperatives (like exhortations to walk in godliness—Ephesians 2:10). The result is a kind of practical antinomianism that shrugs at sin in a believer’s life while pointing to the completed work of Christ.
But that imbalanced emphasis on God’s grace undercuts the importance of cultivating a life of integrity. In fact, it makes it virtually impossible. Consider this definition from John MacArthur’s book The Power of Integrity:
Integrity essentially means being true to one’s ethical standards, in our case, God’s standards. Its synonyms are honesty, sincerity, incorruptibility. It describes someone without hypocrisy or duplicity—someone who is completely consistent with his or her stated convictions. A person who lacks integrity—who says one thing and does another—is a hypocrite.  John MacArthur, The Power of Integrity (Wheaton, IL: Crossway, 1997), ix.
If a believer is to live with integrity, he cannot compromise on Scripture’s exhortations to “deny ungodliness and worldly desires,” “to lay aside the old self,” “to live sensibly, righteously and godly,” and walk in the good works for which the Lord has called and transformed us.
In fact, applying God’s grace as an immediate free pass for your sin is the height of duplicity. It’s an overt denial of the Spirit’s sanctifying work within you, and it trains you to take both your sin and God’s grace lightly. It breeds carelessness and corruption, and can lead to tragic spiritual shipwreck.
Living with integrity means avoiding legalism and lawlessness, and the hypocrisy inherent in both extremes. Instead, we need to pursue the balance Paul strikes in his letter to the Ephesians—one that clings to the gospel while pursuing holiness:
But God, being rich in mercy, because of His great love with which He loved us, even when we were dead in our transgressions, made us alive together with Christ (by grace you have been saved) and raised us up with Him, and seated us with Him in the heavenly places in Christ Jesus. . . . For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; not as a result of works, so that no one may boast. For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand so that we would walk in them. (Ephesians 2:4-10)