7:7-13 There is no way of coming to that knowledge of sin, which is necessary to repentance, and therefore to peace and pardon, but by trying our hearts and lives by the law. In his own case the apostle would not have known the sinfulness of his thoughts, motives, and actions, but by the law. That perfect standard showed how wrong his heart and life were, proving his sins to be more numerous than he had before thought, but it did not contain any provision of mercy or grace for his relief. He is ignorant of human nature and the perverseness of his own heart, who does not perceive in himself a readiness to fancy there is something desirable in what is out of reach. We may perceive this in our children, though self-love makes us blind to it in ourselves. The more humble and spiritual any Christian is, the more clearly will he perceive that the apostle describes the true believer, from his first convictions of sin to his greatest progress in grace, during this present imperfect state. St. Paul was once a Pharisee, ignorant of the spirituality of the law, having some correctness of character, without knowing his inward depravity. When the commandment came to his conscience by the convictions of the Holy Spirit, and he saw what it demanded, he found his sinful mind rise against it. He felt at the same time the evil of sin, his own sinful state, that he was unable to fulfil the law, and was like a criminal when condemned. But though the evil principle in the human heart produces sinful motions, and the more by taking occasion of the commandment; yet the law is holy, and the commandment holy, just, and good. It is not favourable to sin, which it pursues into the heart, and discovers and reproves in the inward motions thereof. Nothing is so good but a corrupt and vicious nature will pervert it. The same heat that softens wax, hardens clay. Food or medicine when taken wrong, may cause death, though its nature is to nourish or to heal. The law may cause death through man's depravity, but sin is the poison that brings death. Not the law, but sin discovered by the law, was made death to the apostle. The ruinous nature of sin, and the sinfulness of the human heart, are here clearly shown.
7, 8. What … then? Is the law sin? God forbid!—"I have said that when we were in the flesh the law stirred our inward corruption, and was thus the occasion of deadly fruit: Is then the law to blame for this? Far from us be such a thought."
Nay—"On the contrary" (as in Ro 8:37; 1Co 12:22; Greek).
I had not known sin but by the law—It is important to fix what is meant by "sin" here. It certainly is not "the general nature of sin" [Alford, &c.], though it be true that this is learned from the law; for such a sense will not suit what is said of it in the following verses, where the meaning is the same as here. The only meaning which suits all that is said of it in this place is "the principle of sin in the heart of fallen man." The sense, then, is this: "It was by means of the law that I came to know what a virulence and strength of sinful propensity I had within me." The existence of this it did not need the law to reveal to him; for even the heathens recognized and wrote of it. But the dreadful nature and desperate power of it the law alone discovered—in the way now to be described.
for I had not known lust, except, &c.—Here the same Greek word is unfortunately rendered by three different English ones—"lust"; "covet"; "concupiscence" (Ro 7:8)—which obscures the meaning. By using the word "lust" only, in the wide sense of all "irregular desire," or every outgoing of the heart towards anything forbidden, the sense will best be brought out; thus, "For I had not known lust, except the law had said, Thou shalt not lust; But sin, taking ('having taken') occasion by the commandment (that one which forbids it), wrought in me all manner of lusting." This gives a deeper view of the tenth commandment than the mere words suggest. The apostle saw in it the prohibition not only of desire after certain things there specified, \ but of "desire after everything divinely forbidden"; in other words, all "lusting" or "irregular desire." It was this which "he had not known but by the law." The law forbidding all such desire so stirred his corruption that it wrought in him "all manner of lusting"—desire of every sort after what was forbidden.