Some wrongly pit the Old Testament against the New Testament, asserting that the OT is law-focused and external while the NT is heart-focused and internal. Even a cursory reading of the OT makes clear that true righteousness always involved internal faith and a transformed heart. You shall love the LORD your God with all your heart and with all your soul and with all your might. And these words that I command you today shall be on your heart (Deut. 6:5-7).
Legalism does not work. It never has and it never will. Legalism is the pursuit of good works — obedience to God’s law and the ethical commands of the Bible (and beyond) — abstracted from faith in Christ in order to be acceptable before God. The legalist approaches the Bible as a law-centered document rather than a Christ-centered one. Legalism attempts to domesticate the law of God and exacerbates sin rather than killing it because it feeds the flesh.
Legalism always produces two kinds of people: Those who know they do not measure up to God’s standards; and those who pretend that they measure up to God’s standards. I have often asked people, “What are your personal standards for what a person should say and do? Have you, in every instance, lived up to your own standards?” The answer is always no. If we haven’t lived up to our own standards, then we can be certain we have not lived up to God’s standards either.
The Problem with the Righteousness of the Scribes and Pharisees
The Sermon on the Mount turns on Matthew 5:20: “For I tell you, unless your righteousness exceeds that of the scribes and Pharisees, you will never enter the kingdom of heaven.” Jesus’s assertion would have been startling to his hearers.