To rebuke our self-righteousness (v. 19)

• The Mosaic Law was not useless in Paul’s eyes. It actually prepares us to receive the Good News of God’s provision first by rebuking our sense of self-righteousness.
• This is one purpose of the Law: to reveal the perfect standard of God & silence the self-righteous, self-justifying tongues of human beings. If you understand the Law, then you understand God’s perfection & you see that you don’t measure up.
• Ray Stedman >> You can always tell someone is close to becoming a Christian when they shut up and stop arguing back. Self-righteous people are always saying, “But – but this – but I – yes, but I do this – and I do that.” They are always arguing. But when they see the true meaning of the Law, their mouth is shut. When you read a statement like this, there is really nothing left to say, is there?”

To reveal the insufficiency of good works (v. 20)

• It cannot be any clearer >> v. 20 | For by works of the law no human being will be justified in his sight, since through the law comes knowledge of sin.
• As human beings, we somehow reason that God, in His fairness, would weight our good works more than our bad works. Then we selectively call to mind our good works as testimony that we are good people, while at the same time suppressing the prevalence of our transgressions & sins against God & others. We don’t realize that God, in His greatness & holiness, is perfect, which means that he doesn’t weight anything of our good deeds or bad deeds, but rather His holiness is such that one bad deed is bad enough to condemn us for all eternity.

Conclusion
• All of God’s image-bearers, created for His glory, stand condemned. What would God do? It seems there are only two options: Let the verdict stand – all His creation be condemned. Or adjust the standard to grade everyone on a curve? Is He a God of justice or a God of mercy?
• Provision has to be made. A substitute has to be provided – on who can uphold God’s standard & bear the unrighteousness of sinners.