First. Add redemption unto mercy, and things are still heightened and more significant. And it must, because the text adds it, and because both the nature of God, the holiness of his law, and the present state of the sinner that is to be saved, requireth that it should be so. God is justice and mercy; the law is holy and just; that man to be saved is not only a sinner but polluted. Now, then, that mercy and justice may meet and kiss in the salvation of the sinner, there must be a redemption; that the sinner may be saved, and the law retain its sanction and authority, there must be a redemption; that the sinner may be purged as well as pardoned, there must be a redemption. And, I say, as there must, so there is: 'For with the Lord there is mercy, and with him is plenteous redemption.' Mercy is our redemption's original cause and manager. Redemption is the manifestation and the completing of that mercy. If there had been no mercy, there had been no redemption. Mercy had been defective as to us, or must have offered violence to the law and justice of God, and have saved us contrary to that word, 'In the day thou eatest thou shalt die,' and 'Cursed is every one that continueth not in all things written in the book of the law to do them.' But now, redemption comes in by mercy, the sin is done away, and the sinner is saved in a way of righteousness.
Second. By law as well as grace; that is, in a way of justice as well as in a way of mercy. Hence it saith we are 'justified freely by his grace, through the redemption that is in Christ Jesus' (Rom 3:24). Through the redemption that is in Jesus Christ, whom God hath set forth to be a propitiation through faith in his blood, and so to show the world the equity of his proceeding with sinners in the saving of their souls. As if God should say to all those who stumble at the salvation of sinners by grace, Behold, I act according to law and justice. For of grace I save them through a redemption, and therefore am faithful and just to my law and free and liberal of my mercy. Wherefore thus I declare I am righteous, loyal, and just in passing over or remitting of sin. Nay, the matter so standeth now betwixt me and the sinful world that I could not be just if I did not justify him that hath faith in the blood of Jesus since by that blood, my justice is appeased for all that this or that sinner has done against my law!
This is a way that neither God nor any child of his need be ashamed of before any that shall call in question the legality and justice of this procedure. Why may not God be merciful, and why may not God be just? And since he can be both merciful and just in the salvation of sinners, why may he not also save them from death and hell? Christ is God's salvation, and to show that he is not ashamed of him, he hath presented him, and the way of redemption by him, before the face of all people (Luke 2:30-32). Nor is the Son, who is become, concerning the act of redemption, the author of eternal salvation, ashamed of this his doings. 'I gave my back to the smiters,' saith he, 'and my cheeks to them that plucked off the hair; I hid not my face from shame and smiting' (Isa 50:6). This he speaks to show what were some of his sufferings when he engaged in the work of our redemption, and how heartily he did bear and go through them. 'For,' says he, 'the Lord God will help me,' that is, justify me in it, 'therefore shall I not be confounded, therefore have I set my face like a flint, and I know that I shall not be ashamed' (v 7). And if God and his Son Jesus Christ are neither ashamed to own this way of salvation, why should the sinners concerned thereabout be afraid thereupon to venture their soul? I know, saith he, 'I shall not be ashamed'; I shall not, that is, when all things come to light, and everything shall appear above board; when the heart and soul of this undertaking of mine shall be proclaimed upon the house-tops, I know I shall not be ashamed.
Upon this account, Paul also said he was not ashamed of the gospel (Rom 1). For he knew that it was a declaration of the highest act of wisdom that ever God did spread before the face of the sons of men. And what wisdom is the gospel? Is it a declaration but of forgiveness of sins by grace, through the redemption that is by the blood of Jesus Christ? 'In whom we have redemption through his blood,' even 'the forgiveness of sins, according to the riches of his grace, wherein he hath abounded toward us in all wisdom and prudence' (Eph 1:7,8).