Adam Clarke on Romans 7:12

Wherefore the law is holy - As if he had said, to soothe his countrymen, to whom he had been showing the absolute insufficiency of the law either to justify or save from sin: I do not intimate that there is any thing improper or imperfect in the law as a rule of life: it prescribes what is holy, just, and good; for it comes from a holy, just, and good God. The Law, which is to regulate the whole of the outward conduct, is holy; and the Commandment, Thou shalt not covet, which is to regulate the heart, is not less so. All is excellent and pure; but it neither pardons sin nor purifies the heart; and it is because it is holy, just, and good, that it condemns transgressors to death.