Christ redeemed us from the curse of the law by becoming a curse for us—for it is written, “Cursed is everyone who is hanged on a tree.”
With gratitude and with a sure confidence, therefore, let us accept this doctrine, so sweet and so filled with comfort, which teaches that Christ became a curse for us … Therefore He truly became accursed according to the Law, not for Himself but, as Paul says, ὑπὲρ ἡμῶν [“on our behalf”]. For unless He had taken upon Himself my sins, your sins, and the sins of the entire world, the Law would have had no right over Him, since it condemns only sinners and holds only them under a curse. Therefore He could neither have become a curse nor have died, since the cause of the curse and of death is sin, of which He was innocent. But because He took upon Himself our sins, not by compulsion but of His own free will, it was right for Him to bear the punishment and the wrath of God—not for His own Person, which was righteous and invincible and therefore could not become guilty, but for our person.
By this fortunate exchange with us He took upon Himself our sinful person and granted us His innocent and victorious Person. Clothed and dressed in this, we are freed from the curse of the Law, because Christ Himself voluntarily became a curse for us, saying: “For My own Person of humanity and divinity I am blessed, and I am in need of nothing whatever. But I shall empty Myself (Phil. 2:7); I shall assume your clothing and mask; and in this I shall walk about and suffer death, in order to set you free from death.” Therefore when, inside our mask, He was carrying the sin of the whole world, He was captured, He suffered, He was crucified, He died; and for us He became a curse. But because He was a divine and eternal Person, it was impossible for death to hold Him. Therefore He arose from death on the third day, and now He lives eternally; nor can sin, death, and our mask be found in Him any longer; but there is sheer righteousness, life, and eternal blessing.
We must look at this image and take hold of it with a firm faith. He who does this has the innocence and the victory of Christ, no matter how great a sinner he is. But this cannot be grasped by loving will; it can be grasped only by reason illumined by faith. Therefore we are justified by faith alone, because faith alone grasps this victory of Christ. … If you believe that sin, death, and the curse have been abolished, they have been abolished, because Christ conquered and overcame them in Himself; and He wants us to believe that just as in His Person there is no longer the mask of the sinner or any vestige of death, so this is no longer in our person, since He has done everything for us.
Therefore if sin makes you anxious, and if death terrifies you, just think that this is an empty specter and an illusion of the devil—which is what it surely is. For in fact there is no sin any longer, no curse, no death, and no devil, because Christ has conquered and abolished all these. Accordingly, the victory of Christ is utterly certain; the defects lie not in the fact itself, which is completely true, but in our incredulity. It is difficult for reason to believe such inestimable blessings. In addition, the devil and the sectarians—the former with his flaming darts (Eph. 6:16), the latter with their perverse and wicked doctrine—are bent on this one thing: to obscure this doctrine and take it away from us. It is above all for this doctrine, on which we insist so diligently, that we bear the hate and persecution of Satan and of the world. For Satan feels the power and the results of this doctrine.
“Lectures on Galatians, 1535,” in Works, 26:283–285.