His reply was, in fact, an accusation against their whole system. He told them, in effect, that all their piety was outward and hypocritical; that they justified, by their own arbitrary statutes, their actual violation of God's holy law, and thought to escape its observance by their sophistical casuistry. Having thus repulsed the Pharisees, he turned to the multitude, and warned them against the Pharisaical tendency so destructive to Jewish piety, the tendency to smother true religion under a mass of outward forms. "Hear and understand; not that which goeth into the mouth defileth a man; but that which cometh out of the mouth, this defileth a man." Here Christ displays the same conscious, lofty superiority so often manifested in his disputes with the Pharisees (as recorded in John, as well as in the synoptical Gospels); instead of softening down the offensive doctrine, he presents it more and more forcibly in proportion as they take offence. The words just quoted might be interpreted as an attack upon the Mosaical law in respect to food, &c., and thus could afford the Pharisees a clear opportunity to fix a charge of heresy upon him.
When the disciples called his attention to the offence which the Pharisees had taken, he gave them to understand that this caused him no uneasiness: Every plant which, my heavenly Father hath not planted shall be rooted up; let them alone; they be blind leaders of the blind; both shall fall into the ditch. ("All merely human growths -- every thing not planted by God -- must fall; the whole Pharisaic system shall come to the ground. Let not their talk trouble you; blind are they, and those that follow them; both leaders and led are going on to destruction.")
The disciples probably expected a different explanation; they were still too much ruled by Jewish views to apprehend correctly the full force of Christ's figurative language. The form of expression was simple enough in itself; it was the strange thought which made it difficult. It was only at a later period that even Peter could learn, and that, too, by the illumination of the Holy Ghost, that every thing is pure, for men, which comes pure from the Creator's hand. In the case before us, Peter, as spokesman for the disciples, asked an explanation of the obscure point. In reply, Christ first expressed his surprise that, after having so long enjoyed his society and teaching, they had made so little progress in religious knowledge; that such a saying should awake their scruples as well as the Pharisees'. "Do ye not yet understand," said he, "that what enters a man's mouth from without cannot defile the interior life? It is the product of the heart, it is that which comes from within that makes a man unclean." This truth was then immediately applied only to the case in point, viz.: eating with unwashed hands; the wider application of which it was capable could not be unfolded to them until a much later period. 
 Cf. p. 88.