How does Jesus address the issue of external vs. internal righteousness?

In Matthew 15:11, Jesus emphasizes that it is not what goes into the mouth that defiles a person but rather what comes out of it. This teaching reflects the heart of His message: external practices, such as ritual purity, cannot make a heart right with God. Instead, the disposition of the heart is what matters. Throughout Scripture, including passages like Romans 2:29, we see that genuine righteousness stems from an inward change brought about by faith in Christ, rather than mere adherence to the law. This shift from external to internal righteousness is critical for understanding true faith in the Christian life.