2 What then says Christ? He did not set Himself against it, neither made He any defense, but straightway blames them again, plucking down their confidence, and signifying that he who commits great sins ought not to be strict with others concerning small matters. “What? When you ought to be blamed,” says He, “do ye even blame?”
But do thou observe, how when it is His will to set aside any of the things enjoined by the law, He does it in the form of an apology; and so He did in that case. For by no means does He proceed at once to transgress it, nor does He say, “It is nothing;” for surely He would have made them more audacious; but first He clean cuts away their boldness, bringing forward the far heavier charge, and directing it upon their head. And He neither says, “they do well in transgressing it,” lest He should give them a hold on Him; nor does He speak ill of their proceeding, lest He should confirm the law: nor again, on the other hand, does He blame the elders, as lawless and unholy men; for doubtless they would have shunned Him as a reviler and injurious: but all these things He gives up, and proceeds another way. And He seems indeed to be rebuking the persons themselves who had come to Him, but He is reprehending them that enacted these laws; nowhere indeed making mention of the elders, but by His charge against the Scribes casting down them also, and signifying that their sin is twofold, first in disobeying God, next in doing so on men's account; as though He had said, “Why this, this has ruined you, your obeying the elders in all things.”
Yet He says not so, but this is just what He intimates, by answering them as follows:
Why do ye also transgress the commandment of God by your tradition? For God commanded, saying, Honor your father and your mother: and, He that curses father or mother, let him die the death. But ye say, Whosoever shall say to his father or his mother, It is a gift, by whatsoever you might be profited by me, and honor not his father or his mother — And you have made void the commandment of God by your tradition.
And He said not, “the elders' tradition,” but “your own.” And, “ye say;” again He said not, “the elders say:” in order to make His speech less galling. That is, because they wanted to prove the disciples transgressors of the law, He signifies that they themselves are doing so, but that these are free from blame. For of course that is not a law, which is enjoined by men (wherefore also He calls it “a tradition”), and especially by men that are transgressors of the law.
And since this had no shade of contrariety to the law, to command men to wash their hands, He brings forward another tradition, which is opposed to the law. And what He says is like this. “They taught the young, under the garb of piety, to despise their fathers.” How, and in what way? “If one of their parents said to his child, Give me this sheep that you have, or this calf, or any such thing, they used to say, 'This is a gift to God, whereby you would be profited by me, and you can not have it.' And two evils hence arose: on the one hand they did not bring them to God, on the other they defrauded their parents under the name of the offering, alike insulting their parents for God's sake, and God for their parents' sake.” But He does not say this at once, but first rehearses the law, by which He signifies His earnest desire that parents should be honored. For, “honor,” says He, “your father and your mother, that you may live long upon the earth.” And again, “He that curses father or mother, let him die the death.”
But He, omitting the first, the reward appointed for them that honor their parents, states that which is more awful, the punishment, I mean, threatened to such as dishonor them; desiring both to dismay them, and to conciliate such as have understanding; and He implies them to be for this worthy of death. For if he who dishonors them in word is punished, much more ye, who do so in deed, and who not only dishonor, but also teach it to others. “You then who ought not so much as to live, how find ye fault with the disciples?”
“And what wonder is it, if you offer such insults to me, who am as yet unknown, when even to the Father you are found doing the like?” For everywhere He both asserts and implies, that from Him they began with this their arrogance.
But some do also otherwise interpret, “It is a gift, by whatsoever you might be profited by me;” that is, I owe you no honor, but it is a free gift from me to you, if indeed I do honor you. But Christ would not have mentioned an insult of that sort.
And Mark again makes this plainer, by saying, “It is Corban, by whatsoever you might be profited by me;” which means, not a gift and present, but properly an offering.
Having then signified that they who were trampling on the law could not be justly entitled to blame men for transgressing a command of certain elders, He points out this same thing again from the prophet likewise. Thus, having once laid hold of them severely, He proceeds further: as on every occasion He does, bringing forward the Scriptures, and so evincing Himself to be in accordance with God.
And what says the prophet? “This people honors me with their lips, but their heart is far from me. But in vain do they worship me, teaching for doctrines the commandments of men.”
Do you see a prophecy in exact accordance with His sayings, and from the very first proclaiming beforehand their wickedness? For what Christ laid to their charge now, of this Isaiah also spoke from the very first; that the words of God they despise, “for in vain do they worship me,” says He; but of their own they make much account, “teaching,” says He, “for doctrines the commandments of men.” Therefore with reason the disciples keep them not.
Source: Homilies on the Gospel of St. Matthew (New Advent)