First, God did give the law that sin might abound, not that it should take away sin in any, but to discover the sin which is already begotten, or that may be hereafter begotten, by lust and Satan (Rom 5:20). I say, this is one proper work of the law, to make manifest sin; it is sent to find fault with the sinner, and it doth also watch that it may do so, and it doth take all advantages for the accomplishing of its work in them that give ear to it, or do not give ear, if it have the rule over them. I say it is like a man sent by his lord to see and pry into the labors and works of other men, taking every advantage to discover their infirmities and failings and to chide them? Yea, to throw them out of the Lord's favor for the same.
Second. Another great reason the Lord did add or give the law was that no man might have anything to lay to the charge of the Lord for His condemning those who transgress against the same. You know that if a man should be had before an officer or judge, and there be condemned, and yet by no law, he that condemns him might be very well reprehended or reproved for passing the judgment; yea, the party himself might have better ground to plead for his liberty than the other to plead for the condemning of him; but this shall not be so in the judgment-day, but contrariwise; for then every man shall be forced to lay his hand on his mouth, and hold his tongue at the judgment of God when it is passed upon them; therefore saith the Apostle, "What things soever the law saith, it saith to them who are under the law"; that is, all the commands, all the cursing and threatening that are spoken by it, are communicated, saith he, "that every mouth may be stopped"; mark, I beseech you, "it saith," saith he, "that every mouth may be stopped, and all the world may become guilty before God" (Rom 3:19). So that now, in case any in the judgment-day should object against the judgment of God, as those in the 25th of Matthew do, saying, Lord, when saw we Thee thus and thus? And why dost Thou pass such a sad sentence of condemnation upon us? Indeed, this is injustice, and not equity: now for the preventing of this the law was given; ay, and that it might prevent thee to purpose, God gave it betimes, before either thy first father had sinned, or thou was born. So that again, if these objections should be offered against the proceedings of the Lord in justice and judgment, saying, Lord, why am I thus condemned? I did not know it was a sin? Now, against these two was the law given and that betimes, so both are answered. If they first come in and say, Why am I judged? Why am I damned? Then will the law come in, even all the Ten Commandments, with every one of their cries against thy soul; the First saying, He hath sinned against Me, damn him; the Second saying also, He hath transgressed against Me, damn him; the Third also saying the same, together with the Fourth, Fifth, Sixth, Seventh, Eighth, Ninth, Tenth; even all of them will discharge themselves against thy soul if thou die under the first covenant, saying, He or they have transgressed against us, damn them, damn them: and I tell thee also, that these ten great guns, the Ten Commandments, will, with discharging themselves in justice against thy soul, so rattle in thy conscience, that thou wilt despite thy teeth be immediately put to silence, and have thy mouth stopped. And let me tell thee further, that if thou shalt appear before God to have the Ten Commandments discharge themselves against thee, thou hadst better be tied to a tree, and have ten, yea, ten thousand of the most significant pieces of ordnance in the world to be shot off against thee; for these could go no further but only to kill the body; but they, both body and soul, to be tormented in Hell with the devil to all eternity.
Third, Again, if the second thing should be objected, saying, But Lord, I did not think this had been sin, or the other had been sin, for nobody told me so, then also will the giving of the law take off that, saying, Nay, But I was given to thy father Adam before he had sinned, or before thou was born, and have ever since been in thy soul to convince thee of thy sins and to control thee for doing the thing that was not right. Did not I secretly tell thee at such a time, in such a place, when thou was doing such a thing, with such a one, or when thou was all alone, that this was a sin, and that God did forbid it, therefore if thou didst commit it, God would be displeased with thee for it: and when thou was thinking to do such a thing at such a time, did not I say, Forbear, do not so? God will smite and punish you if thou dost do it. And besides, God did so order it that you had me in your houses, in your Bibles, and also you could speak and talk of me; thus pleading the truth, thou shalt be forced to confess it is so; nay, it shall be so in some sort with the very Gentiles and barbarous people that fall far short of that light we have in these parts of the world; for, saith the Apostle, "The Gentiles which have not the law, do by nature the things contained in the law, these, having not the law," that is, not written as we have, yet they "are a law unto themselves: which show the works of the law written in their hearts" (Rom 2:14,15). That is, they have the law of works in them by nature, and therefore they shall be left without excuse; for their own consciences shall stand up for the truth of this where he saith, "Their conscience also bearing witness, and their thoughts the meanwhile accusing or else excusing one another." Ay, but when? Why, "in the day when God shall judge the secrets of men by Jesus Christ according to my Gospel" (Rom 2:15,16). So this, I say, is another end for which the Lord did give the law—namely, that God might pass a sentence in righteousness without being charged with any injustice by those that shall fall under it in the judgment.
