Well, if ever you thought you were good enough to earn something from God then look at verse 6 and think again. "For all of us have become like one who is unclean, and all our righteous deeds are like a filthy garment."
Beloved, no matter how good you think you are, no matter how much you think you deserve hear the words of your Maker - your BEST deeds are like a filthy, soiled, refuse soaked rag. We have nothing to offer Him but our sin.
In question 91, the Heidelberg Catechism asks "what are good works?" The answer it gives is threefold. Good works are only those that "proceed from a true faith (Rom 14:23), are performed according to the law of God (Rom 7:7), and to His glory (1 Co 10:31), and not such as are founded on our imaginations, or the institutions of men."
Take a look at those words again. Look at the marks that biblically define a deed as good: performed from true faith, performed according to the law of God, and performed for His glory. Even if we happened to get the first two right, how rarely do we truly do things for His glory - really, honestly, and fully for His glory. Yes, indeed even our BEST deeds are like filthy garments.
Friends, we desperately need the righteousness of Christ imputed to us. It is ONLY in and through Him that anything good dwells in us and flows from us. What garments are you walking in this day? Your filthy rags or the righteous robes of the Lord Jesus Christ?