Thou who gloriest in the law, etc. Though every transgressor dishonors God, (for we are all born for this end -- to serve him in righteousness and holiness;) yet he justly imputes in this respect a special fault to the Jews; for as they avowed God as their Lawgiver, and yet had no care to form their life according to his rule, they clearly proved that the majesty of their God was not so regarded by them, but that they easily despised him. In the same manner do they at this day dishonor Christ, by transgressing the gospel, who prattle idly about its doctrine, while yet they tread it under foot by their unbridled and licentious mode of living.

Makest thy boast - To boast in the Law implied their conviction of its excellence and obligation, as a man does not boast of what he esteems to be of no value.
Dishonourest thou God - By boasting of the Law, they proclaimed their conviction that it was from God. By breaking it, they denied it. And as actions are a true test of man's real opinions, their breaking the Law did it more dishonor than their boasting of it did it honor. This is always the case. It matters little what a man's speculative opinions may be; his practice may do far more to disgrace religion than his profession does to honor it. It is the life and conduct, and not merely the profession of the lips, that does real honor to the true religion. Alas, with what pertinency and force may this question be put to many who call themselves Christians!

Thou that makest thy boast of the law,.... Of their having it, which other nations had not; of their knowledge of it, which many of their own people were without, or had but a small share of; and of their keeping of it even to perfection:
through breaking of the law dishonourest thou God? sin sometimes is expressed by a word which signifies a "fall"; sometimes by another, which signifies missing of the mark, or straying from it; sometimes by another, which signifies a "contrariety to the law" of God; and here, by one which signifies a "passing over it", and the bounds which it has set, as the rule of man's obedience; and hereby God, the lawgiver, is dishonoured: for as God is glorified by good works, when rightly performed, he is dishonoured by evil ones; for his authority, as a lawgiver, is trampled upon and despised. Now persons guilty of such iniquities as here mentioned, could not be justified before God, or accepted by him on account of any works of righteousness done by them.