Standing before God clothed in the righteousness that is our own faith?

Mike Shea on Romans 5:1 and 5:9-

Faith does not merit you justification on some kindler and gentler New Testament sliding scale. No, faith receives the gift of perfect righteousness, purchased for you by the blood of Christ. Faith doesn't purchase the righteousness, faith doesn't merit the righteousness, faith simply receives the gift of righteousness purchased by the blood of Christ, and so Paul can say we are justified by His blood. We do not stand before God clothed in the righteousness that is our own faith; we stand before God clothed in the perfect righteousness of Christ, received through faith. And it makes a difference! If you don't get this, you'll have a very shaky assurance, because you'll be in danger of trusting in your own faith, rather than trusting in Christ. If you think that your faith merits the justification, that God's lowered His standards and says, "Okay, just believe," and you worry, "Well... do I believe enough? Is my faith strong enough?!" Your assurance will only be as stable as your own faith, rather than your assurance being as stable as the faithfulness of Christ.