http://www.ccel.org/ccel/calvin/institutes.iv.xvii.html
The very form of the death embodies a striking truth. The cross was cursed not only in the opinion of men, but by the enactment of the Divine Law. Hence Christ, while suspended on it, subjects himself to the curse. And thus it behoved to be done, in order that the whole curse, which on account of our iniquities awaited us, or rather lay upon us, might be taken from us by being transferred to him. This was also shadowed in the Law, since the word by which sin itself is properly designated, was applied to the sacrifices and expiations offered for sin. By this application of the term, the Spirit intended to intimate, that they were a kind of kaqarmavton (purifications), bearing, by substitutions the curse due to sin. But that which was represented figuratively in the Mosaic sacrifices is exhibited in Christ the archetype. Wherefore, in order to accomplish a full expiation, he made his soul a propitiatory victim for sin (as the prophet says, Is. 53:5, 10), on which the guilt and penalty being in a manner laid, ceases to be imputed to us. The Apostle declares this more plainly when he says, that “he made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him,” (2 Cor. 5:21). For the Son of God, though spotlessly pure, took upon him the disgrace and ignominy of our iniquities, and in return clothed us with his purity. To the same thing he seems to refer, when he says, that he “condemned sin in the flesh,” (Rom. 8:3), the Father having destroyed the power of sin when it was transferred to the flesh of Christ. This term, therefore, indicates that Christ, in his death, was offered to the Father as a propitiatory victim; that, expiation being made by his sacrifice, we might cease to tremble at the divine wrath. It is now clear what the prophet means when he says, that “the Lord has laid upon him the iniquity of us all,” (Is. 53:6); namely, that as he was to wash away the pollution of sins, they were transferred to him by imputation. Of this the cross to which he was nailed was a symbol, as the Apostle declares, “Christ has redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth 440on a tree: that the blessing of Abraham might come on the Gentiles through Jesus Christ,” (Gal. 3:13, 14). In the same way Peter says, that he “bare our sins in his own body on the tree,” (1 Peter 2:24), inasmuch as from the very symbol of the curse, we perceive more clearly that the burden with which we were oppressed was laid upon him. Nor are we to understand that by the curse which he endured he was himself overwhelmed, but rather that by enduring it he repressed broke, annihilated all its force. Accordingly, faith apprehends acquittal in the condemnation of Christ, and blessing in his curse. Hence it is not without cause that Paul magnificently celebrates the triumph which Christ obtained upon the cross, as if the cross, the symbol of ignominy, had been converted into a triumphal chariot. For he says, that he blotted out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross: that “having spoiled principalities and powers he made a show of them openly, triumphing over them in it,” (Col. 2:14, 15). Nor is this to be wondered at; for, as another Apostle declares, Christ, “through the eternal Spirit, offered himself without spot to God,” (Heb. 9:14), and hence that transformation of the cross which were otherwise against its nature. But that these things may take deep root and have their seat in our inmost hearts, we must never lose sight of sacrifice and ablution. For, were not Christ a victim, we could have no sure conviction of his being ajpoluvtrwsi”, ajntivlutron, kai; iJlasthvrion, our substitute-ransom and propitiation. And hence mention is always made of blood whenever scripture explains the mode of redemption: although the shedding of Christ’s blood was available not only for propitiation, but also acted as a laver to purge our defilements.