But in vain do they worship me The words of the prophet run literally thus: their fear toward me has been taught by the precept of men. But Christ has faithfully and accurately given the meaning, that in vain is God worshipped, when the will of men is substituted in the room of doctrine. By these words, all kinds of will-worship, (ethelothzeskeia,) as Paul calls it, (Colossians 2:23,) are plainly condemned. For, as we have said, since God chooses to be worshipped in no other way than according to his own appointment, he cannot endure new modes of worship to be devised. As soon as men allow themselves to wander beyond the limits of the Word of God, the more labor and anxiety they display in worshipping him, the heavier is the condemnation which they draw down upon themselves; for by such inventions religion is dishonored. Teaching doctrines, commandments of men In these words there is what is called apposition; [1] for Christ declares them to be mistaken who bring forward, in the room of doctrine, the commandments of men, or who seek to obtain from them the rule for worshipping God. Let it therefore be held as a settled principle, that, since obedience is more highly esteemed by God than sacrifices, (1 Samuel 15:22,23,) all kinds of worship invented by men are of no estimation in his sight; nay more, that, as the prophet declares, they are accursed and detestable.

Footnotes

1 - "C'est une figure et facon de parler que les Latins nomment Apposition;" -- "it is a figure and mode of speech which the Latins call Apposition." -- "The Latin Grammarians employ the word Appositio to denote a figure, by which two words, denoting the same thing, are put in the same case, such as, Urbs Roma, Fluvius Sequana In the same sense the Greek word epexegesis was often used. -- Ed.

In vain do they worship me - That is, their attempts to worship are "vain," or are not real worship - they are mere "forms."
Teaching for doctrines - The word "doctrines," here, means the requirements of religion - things to be believed and practiced in religion.
God only has a right to declare what shall be done in his service; but they held their traditions to be superior to the written word of God, and taught them as doctrines binding the conscience. See the notes at Isaiah 29:13.

In vain they do worship me, etc. - By the traditions of the elders, not only the word of God was perverted, but his worship also was greatly corrupted. But the Jews were not the only people who have acted thus: whole Christian Churches, as well as sects and parties, have acted in the same way. Men must not mould the worship of God according to their fancy - it is not what they think will do - is proper, innocent, etc., but what God himself has prescribed, that he will acknowledge as his worship. However sincere a man may be in a worship of his own invention, or of man's commandment, yet it profits him nothing. Christ himself says it is in vain. To condemn such, may appear to some illiberal; but whatever may be said in behalf of sincere heathens, and others who have not had the advantages of Divine Revelation, there is no excuse for the man who has the Bible before him.

But in vain do they worship me,.... In the Hebrew text it is, "their fear towards me": which is rightly expressed here by "worship"; for the fear of God often intends the whole worship of God, both external and internal: here it only signifies external worship, which these men only attended to. They prayed in the synagogues, read, and, in their way, expounded the books of Moses, and the prophets, to the people, diligently observed the rituals of the ceremonial law, brought their offerings and sacrifices to the temple, and neglected nothing appertaining to the outward service of it; and yet it was all "in vain", and to no purpose; since the heart was wanting, no grace there, they acted from wrong principles, and with wrong views; their worship was merely outward, formal, and customary; and besides, they added doctrines and traditions of their own inventing and devising. The phrase, "in vain", is not in the text in Isaiah: some have thought that it was not originally in Matthew, but inserted by some other hand, to make the sense more complete. Grotius thinks there was a various reading, which is followed by the Septuagint, and the evangelist; and that instead of "and is", it was the same with "in vain": but there is no need to suppose either of these: Christ, who made this citation, either added it himself for the clearer illustration of the passage, and as being entirely agreeable to the sense of it, and which it required, for the true understanding of it; or he might have in his view another passage of the same prophet, speaking of the same people, and upon the same subject, Isaiah 1:11 and from thence take the phrase, and, for explanation sake, join it to the passage here. It follows,
teaching for doctrines the commandments of men; that is, teaching the people to observe the traditions of the elders, the decrees and determinations of the doctors, as if they were doctrines delivered by God himself; or, instead of the doctrines contained in the Bible, which lay neglected by them, they obtruded on them the orders, and injunctions of men. In the text in Isaiah, are only these words, "taught by the precept of men": and which relate to their fear and worship of God; and which is here interpreted of their teachers teaching them it, and that explained of the commandments of men; as if, instead of "taught", it had been read, "teaching". The Jews have no reason to quarrel with this construction and sense, since their Targum paraphrases it thus; "and their fear before me is, , according to the commandment of men that teach": and a noted commentator (c) of their's has this remark on the text, "their fear towards me is" not with a perfect heart, but "by the commandment , of the men that teach them".
(c) R. Song. Jarchi in Isaiah. xxix. 13.

In vain do they worship me. This worship is all idle, empty, and without profit, because they teach as doctrines the commandments of men. This rebuke to the Pharisees, who had added to the law of Moses many traditional human precepts, applies equally to all modern religionists who have modified or added to the Christianity of Christ and the apostles. Whatever one cannot find in the New Testament is of such a character; observance of saints' days, of Christmas, of Lent, the removal of the cup in the Lord's Supper from the laity, infant sprinkling, party creeds and party shibboleths, are all of men and not of God. The devout worshiper should go right to the New Testament for his religion, and reject every ordinance or precept that is not to be found there.

Teaching the commandments of men - As equal with, nay, superior to, those of God. What can be a more heinous sin?