What enters his mouth: Jesus may have been speaking about foods that the law did not allow (such as pork or shellfish) or food made unclean by unwashed hands (Matthew 15:20).
What makes a person defiled also makes them unfit to be with God. Jesus moved the focus from outward rules of purity to the true purity of the heart (see 15:18–19; 23:25–26; Acts 10:1–48; Romans 14:14).
A person’s words show their true character (see Matthew 15:18–20; James 3:1–12).