Also unto thee, O Lord, belongeth mercy; for thou renderest to every man according to his work.
— Psalm 62 v.12

If there be no satisfaction to justice in the mere punishment of the wrong-doer, what shall we say of the notion of satisfying justice by causing one to suffer who is not the wrong-doer? And what, moreover, shall we say to the notion that, just because he is not the person who deserves to be punished, but is absolutely innocent, his suffering gives perfect satisfaction to the perfect justice? That the injustice be done with the consent of the person maltreated makes no difference: it makes it even worse, seeing, as they say, that justice requires the punishment of the sinner, and here is one far more than innocent. They have shifted their ground; it is no more punishment, but mere suffering the law requires! The thing gets worse and worse. Rather than believe in a justice—that is, a God—to whose righteousness, abstract or concrete, it could be any satisfaction for the wrong-doing of a man that a man who did no wrong should suffer, I would be driven from among men, and dwell with the wild beasts that have not reason enough to be unreasonable. What! God, the father of Jesus Christ, like that! The anger of him who will nowise clear the guilty, appeased by the suffering of the innocent! How did it ever come to be imagined? It sprang from the trustless dread that cannot believe in the forgiveness of the Father; cannot believe that even God will do anything for nothing; cannot trust him without a legal arrangement to bind him. It sprang from the pride that will understand what it cannot, before it will obey what it sees. He that insists on understanding first will believe a lie—a lie from which obedience alone will at length deliver him.


by Jess Lederman

In today's entry, MacDonald directly addresses the doctrine of penal substitution. Reformed theology is so prevalent in some parts of the world that it is easy to think of this doctrine as the Official Christian Point of View. Thankfully, my rebirth from above was midwifed by MacDonald and Lewis, and, while MacDonald wasn't much given to proof-texting, Jesus' emphasis on the Fatherhood of God--that He is better than the best mortal father!--was all I needed to validate the Scotsman's understanding of the atonement. 

Below are some other perspectives on penal substitution: 

Roman Catholic

From Nick's Catholic Blog

"And just as Thomas explains Jesus making atonement by means of suffering out of love and obedience, so too the Catechism explains it: "It is love to the end that confers on Christ's sacrifice its value as redemption and reparation, as atonement and satisfaction" (CCC#616). And the Compendium says on paragraph 122: "Jesus freely offered his life as an expiatory sacrifice, that is, he made reparation for our sins with the full obedience of his love unto death."  Notice that it's not receiving our punishment in which atonement is made, but rather the good work of Christ's commitment to loving sinful man even in the midst of persecution, hence why Christ's sacrifice is called a "pleasing aroma" in Ephesians 5:2 (as opposed to the stench of guilt which arouses God's wrath).

On the other hand, the Protestant view of "atonement" is that in which the guilt and punishment due to one person is transferred over to another. This Protestant understanding of atonement is foreign to Catholic tradition and the Bible. (More on this later.) In the true meaning of atonement, nothing logically demands nor requires guilt and punishment to be transferred. This also explains why the Catholic side speaks of Christ offering up a sacrifice while the Protestant side speaks of (God's) wrath being poured down on the sacrifice."

The Eastern Orthodox

"The penal substitution view was completely absent from the church for over 1,000 years. It was only in the 11th century that Anselm of Canterbury began to introduce the groundwork for this kind of theology to the West. Nor was it fully developed into the doctrine we now know as penal substitution until the 16th-century Reformers came along. To this day it has never been accepted in the east (nor has it ever been fully accepted by the Roman Catholics)."
--Alexander Renault

Renault's article, Orthodox Problems with Penal Substitution, is well worth reading. 

Anglican: N.T. Wright, from his book, The Day the Revolution Began

"Here is a point that must be noted most carefully. Paul does not say that God punished Jesus. He declares that God punished Sin in the flesh of Jesus. Now, to be sure, the crucifixion was no less terrible an event because, with theological hindsight, the apostle could see that what was being punished was Sin itself rather than Jesus himself…

The death of Jesus, seen in this light, is certainly penal. It has to do with the punishment on Sin—not, to say it again, on Jesus—but it is punishment nonetheless. Equally, it is certainly substitutionary: God condemned Sin (in the flesh of the Messiah), and therefore sinners who are “in the Messiah” are not condemned. The one dies, and the many do not…But this substitution finds its true meaning not within the normal “works contract,” but within the God-and-Israel narrative, the vocational narrative, the story in accordance with the Bible. Once we rescue this substitution from its pagan captivity, it can resume its rightful place at the heart of the Jewish and then the messianic narrative, the story through which—in 8:4 as elsewhere—humans are rescued not so they can “go to heaven,” but so that “the right and proper verdict of the law could be fulfilled in us, as we live not according to the flesh but according to the spirit.” Humans are rescued in order to be “glorified,” that is, so that they may resume the genuine human existence, bearing the divine image, reflecting God’s wisdom and love into the world…That is why, second, the result is not that sinners are free to “go to heaven,” but that they are free for the true human vocation, the royal priesthood in all its variations.  [287-290]"