A farther knowledge of sin, upon all accounts whatever, is giver by the law; that law which was “added because of transgressions.” This Gal. iii. 19; Rom. vii. 13. revives doctrinally all that sense of good and evil which was at first implanted in man; and it is a glass, whereinto whosoever is able spiritually to look, may see sin in all its ugliness and deformity. The truth is, look upon the law in its purity, holiness, compass, and perfection; its manner of delivery, Exod. xix. 18–20; Deut. iv. 11; Heb. xii. 18–21. with dread, terror, thunder, earthquakes, fire; the sanction of it, in death, curse, wrath; and it makes a wonderful discovery of sin, upon every account: its pollution, guilt, and exceeding sinfulness are seen by it. But yet all this doth not suffice to give a man a true and thorough conviction of sin. Not but that the glass is clear, but of ourselves we have not eyes to look into it; the rule is straight, but we cannot apply it: and therefore Christ sends his Spirit to convince the world of sin, John xvi. 8; who, though, as to some ends and purposes, he makes use of the law, yet the work of conviction, which alone is a useful knowledge of sin, is his peculiar work. And so the discovery of sin may also be said to be by Christ, — to be part of the wisdom that is hid in him. But yet there is a twofold regard besides this, of his sending his Spirit to convince us, wherein this wisdom appears to be hid in him:— First, because there are some near concernments of sin, which are more clearly held out in the Lord Christ’s being made sin for us, than any other way. Secondly, in that there is no knowledge to be had of sin, so as to give it a spiritual and saving improvement, but only in him.