3 Having, you see, given them their mortal blow; and from the facts first, then from their own suffrage, then from the prophet having aggravated the charge, with them indeed He discourses not at all, incorrigibly disposed as they are now come to be, but directs His speech to the multitudes, so as to introduce His doctrine, great and high, and full of much strictness; and taking occasion from the former topic, He proceeds to insert that which is greater, casting out also the observance of meats.
But see when. When He had cleansed the leper, when He had repealed the Sabbath, when He had shown Himself King of earth and sea, when He had made laws, when He had remitted sins, when He had raised dead men, when He had afforded them many proofs of His Godhead, then He discourses of meats.
For indeed all the religion of the Jews is comprised in this; if you take this away, you have even taken away all. For hereby He signifies, that circumcision too must be abrogated. But of Himself He does not prominently introduce this (forasmuch as that was older than the other commandments, and had higher estimation), but He enacts it by His disciples. For so great a thing was it, that even the disciples after so long a time being minded to do it away, first practise it, and so put it down.
But see how He introduces His law: how “He called the multitude, and said unto them, Hear and understand.”
Thus He does by no means simply reveal it to them, but by respect and courtesy, first, He makes His saying acceptable (for this the evangelist declares by saying, “He called them unto Him”): and secondly, by the time also; in that after their refutation, and His victory over them, and the accusation by the prophet, then He begins His legislation, when they too would more easily receive His sayings.
And He does not merely call them unto Him, but also makes them more attentive. For “understand,” says He, that is, “consider, rouse yourselves; for of that sort is the law now about to be enacted. For if they set aside the law, even unseasonably, for their own tradition, and you hearkened; much more ought ye to hearken unto me, who at the proper season am leading you unto a higher rule of self restraint.”
And He did not say, “The observance of meats is nothing, neither that Moses had given wrong injunctions, nor that of condescension He did so;” but in the way of admonition and counsel, and taking His testimony from the nature of the things, He says: “Not the things that go into the mouth, defile the man, but the things that go out of the mouth;” resorting to nature herself both in His enactment and in His demonstration. Yet they hearing all this, made no reply, neither did they say, “What sayest Thou? When God has given charges without number concerning the observance of meats, do you make such laws?” But since He had utterly stopped their mouths, not by refuting them only, but also by publishing their craft, and exposing what was done by them in secret, and revealing the secrets of their mind; their mouths were stopped, and so they went away.
But mark, I pray you, how He does not yet venture distinctly to set Himself with boldness against the meats. Therefore neither did He say “the meats,” but, “the things that enter in defile not the man;” which it was natural for them to suspect concerning the unwashen hands also. For He indeed was speaking of meats, but it would be understood of these matters too.
Why, so strong was the feeling of scruple about the meats, that even after the resurrection Peter said, “Not so, Lord, for I have never eaten anything common or unclean.” For although it was for the sake of others that He said this, and in order to leave Himself a justification against his censurers, by pointing out that he actually remonstrated, and not even so was excused, nevertheless it implies the depth of their impression on that point.
Wherefore you see He Himself also at the beginning spoke not openly concerning meats, but, “The things that go into the mouth;” and again, when He had seemed afterwards to speak more plainly, He veiled it by His conclusion, saying, “But to eat with unwashen hands defiles not the man:” that He might seem to have had His occasion from thence, and to be still discoursing of the same. Therefore He said not, “To eat meats defiles not a man,” but is as though He were speaking on that other topic; that they may have nothing to say against it.
Source: Homilies on the Gospel of St. Matthew (New Advent)