Matthew 15:11 - Ellicott's Commentary On The Whole Bible

Not that which goeth into the mouth. — Up to this time the question had been debated indirectly. The scribes had been convicted of unfitness to speak with authority on moral questions. Now a great broad principle is asserted, which not only cut at the root of Pharisaism, but, in its ultimate tendency. swept away the whole Levitical system of ceremonial purity — the distinction between clean and unclean meats and the like. It went, as the amazement of the disciples showed, far beyond their grasp as yet. Even after the day of Pentecost, Peter still prided himself on the observance of the Law which was thus annulled, and boasted that he had never “eaten anything common or unclean” (Acts 10:14). So slow were even those who had sat at the feet of Jesus to take in the thought that purity was inward and not outward, a spiritual and not a physical quality.