Matthew 15:18

Out of the mouth (ek tou stomato). Spoken words come out of the heart and so are a true index of character. By "heart" (kardia) Jesus means not just the emotional nature, but the entire man, the inward life of "evil thoughts" (dialogismoi ponhroi) that issue in words and deeds. "These defile the man," not "eating with unwashed hands." The captious quibblings of the Pharisees, for instance, had come out of evil hearts.