For the letter (i.e. the law) killeth, but the spirit (i.e. the gospel) giveth life. This is the reason why God hath made Paul the minister of the spirit. ‘God had made us able ministers not of the law but of the gospel, for the law kills, but the gospel gives life.’ This passage and the following context present two important questions. First, in what sense does the law kill? And second, How is it that the apostle attributes to the Mosaic system this purely legal character, when he elsewhere so plainly teaches that the gospel was witnessed or taught both in the law and the prophets? As to the former of these questions, the answer furnished by the Scriptures is plain. The law demands perfect obedience. It says, “Do this and live,” Rom. 10:5; Gal. 3:12, and “Cursed is every one who continueth not in all things written in the book of the law to do them,” Gal. 3:10. As no man renders this perfect obedience, the law condemns him. It pronounces on him the sentence of death. This is one way in which it kills. In the second place, it produces the knowledge or consciousness of sin, and of course of guilt, that is, of just exposure to the wrath of God. Thus again it slays. And thirdly, by presenting the perfect standard of duty, which cannot be seen without awakening the sense of obligation to be conformed to it, while it imparts no disposition or power to obey, it exasperates the soul and thus again it brings forth fruit unto death. All these effects of the law are systematically presented by the apostle in the 6th and 7th chapters of his epistle to the Romans, and in the 3d chapter of the epistle to the Galatians.
—Charles Hodge, An Exposition of the Second Epistle to the Corinthians (New York: A. C. Armstrong & Son, 1891), 56. (HT: S. M. Baugh/Jack Miller)