Do ye not understand - The meaning of this may be thus expressed: The food which is eaten does not affect the mind, and therefore cannot pollute it.
The doctrine of the Pharisees, that neglect of washing and of similar observances defiles a man, cannot be true. Those things pertain to the body as much as food does, and they cannot affect the soul. That must be purified by something else than external washing, and it is polluted by other things than a neglect of mere outward ceremonies. The seat of corruption is within - it is the heart itself; and if people would be made pure, this must be cleansed. If that is corrupt, the whole man is corrupt.

Cast out into the draught - Εις αφεδωνα, - And beeth into the forthgoing a sent - what is not fit for nourishment is evacuated; is thrown into the sink. This I believe to be the meaning of this difficult and variously translated word, αφεδρων. Diodati translates it properly, nella latrina, into the privy. And the Persian translator has given a good paraphrase, and appears to have collected the general meaning her teche der dehen ander ayeed, az nusheeb beeroon rood, we ber zemeen aftad: "Whatsoever enters into the mouth goes downward, and falls upon the ground." Michaelis, and his annotator, Dr. Marsh, have been much perplexed with this perplexing passage. See Michaelis's Introduction, vol. i. note 35. p. 458.

Do not ye understand,.... You must understand, you cannot be so ignorant,
that whatsoever entereth in at the mouth, goeth into the belly, and is cast out into the draught? that is, that whatsoever food a man takes in at his mouth, he swallows down, and it is received into his stomach; which, having performed its office, the grosser parts go down into the belly, and passing through the bowels, are evacuated into the vault, or privy, "purging all meats", as Mark says; for that only receives the filth and excrementitious matter; so that what is left in the body is pure, wholesome, and nourishing: nor can any part of what goes into a man defile him, because it only enters into the body, and passes through it; and, as Mark says, "entereth not into the heart", which is the seat of moral impurity; so that no moral pollution can be contracted by eating any sort of food, even though it should not be clean itself, nor be eaten with clean hands.

Do not ye yet understand that whatsoever entereth in at the mouth, &c.--Familiar though these sayings have now become, what freedom from bondage to outward things do they proclaim, on the one hand; and on the other, how searching is the truth which they express--that nothing which enters from without can really defile us; and that only the evil that is in the heart, that is allowed to stir there, to rise up in thought and affection, and to flow forth in voluntary action, really defiles a man!

Are ye also yet without understanding - How fair and candid are the sacred historians? Never concealing or excusing their own blemishes.