John Calvin Commentary Isaiah 1:14

"Your new moons and your appointed feasts my soul hateth; they are a trouble unto me; I am weary of bearing them." — Isaiah 1:14 (ASV)

Your new-moons. The Prophet adds nothing new to his former doctrine. Regarding all ceremonies in which there is no spiritual truth but only the glare of a false pretense, he declares generally that they are not merely useless but wicked.

Therefore, we should observe that we labor in vain if we do not worship God in the right manner and as God Himself commands. In all things God delights in truth, but especially in the worship due to His majesty. Besides, not only do we labor in vain, but the worship of God (as we have already said) is perverted, and nothing can be more wicked than this. Now, all superstitions are various corruptions of the worship of God; it follows, therefore, that they are wicked and unlawful.

Superstition may be viewed either in itself or in the disposition of the mind. In itself, it is when people have the audacity to devise what God has not commanded. Such are those actions which spring from will-worship (ἐθελοθρησκεία, Colossians 2:23), which is commonly called devotion. One person sets up an idol, another builds a chapel, another appoints annual festivals, and innumerable things of the same nature.

When people venture to take such liberties as to invent new modes of worship, that is superstition. In the disposition of the mind, superstition also occurs when people imitate lawful services that God approves, but keep their whole attention fixed on the outward form and do not pay attention to their purpose or truth.

In this manner, the Jews earnestly adhered to the ceremonies which Moses had commanded but left out what was of the greatest importance. For they paid no regard to a pure conscience, never mentioned faith and repentance, had no knowledge of their guilt, and—what was still worse—separated Christ from them and left no room for the truth.

This plainly shows, as I have already stated, that it was a spurious and deceitful mask, so that their sacrifices did not differ at all from the sacrifices of the Gentiles. It is therefore not surprising that the Lord calls them abomination.

I will not pause to detail the various phrases used here, yet they should not be passed over lightly. For the Lord perceives how great is the wantonness of people in devising modes of worship; therefore, He heaps up a variety of expressions so that He may more powerfully restrain that wantonness, and He declares again that those actions are hateful to Him. Moreover, because people flatter themselves and foolishly entertain the belief that the Lord will hold in some estimation the idle contrivances they have framed, He declares, on the contrary, that He regards them with detestation and abhorrence.