Love, patience, humility, and kindness wrapped around truth cleans the INSIDE of a person. Anger, fear mongering, rules, threats, and judgment of man cleans the OUTSIDE of the person.
The truth of love cleans behavior. The threat of law covers behavior.
Matthew 23:26-28 (NIV)
"Blind Pharisee! First clean the inside of the cup and dish, and then the outside also will be clean."