Romans 2:21 Thou therefore which teachest another, teachest thou not thyself? thou that preachest a man should not steal, dost thou steal? 22 Thou that sayest a man should not commit adultery, dost thou commit adultery? thou that abhorrest idols, dost thou commit sacrilege? 23 Thou that makest thy boast of the law, through breaking the law dishonourest thou God? 24 For the name of God is blasphemed among the Gentiles through you, as it is written.
The Jews saw the law as their salvation. Look at the pharisees. They had established themselves as a different class in society. They felt their religious actions put them above others. They could not see the sin in their hearts because they were so full of themselves.
Luke 18:10 Two men went up into the temple to pray; the one a Pharisee, and the other a publican. 11 The Pharisee stood and prayed thus with himself, God, I thank thee, that I am not as other men are, extortioners, unjust, adulterers, or even as this publican. 12 I fast twice in the week, I give tithes of all that I possess.
The pharisees had put themselves above other Jews. The Jews would then put themselves in general above Gentiles. They saw the law as their standing before God. What they did not see was they themselves were not keeping the law. They had knowledge of the law and ways of God but failed to see their sin. They did not see the need for a savior. The law not only was displayed in actions but in the attitudes of those who “followed” the law. It was not just an outward following but an inward as well.
Matthew 5:28 But I say unto you, That whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.
None could say they followed the law to the standard God requires. The Jews, primarily the religious ruling class, would paint themselves as right before God by their works of law. Paul is quick to show that this is a false sense of security as none can stand in the presence of the holiness of God. They were fooling themselves. They were blind to their need before God. None can escape the judgment of God. All are in need of salvation.