The Doctrine of Vicarious Redemption
"He himself bore our sins in his body on the tree, that we might die to sin and live to righteousness," (1 Peter 2:24) and "For Christ also died for sins once for all, the righteous for the unrighteous, that he might bring us to God," (1 Peter 3:18). These are two biblical quotes that from which Christianity's foundational dogma arose.
The word; atonement, meaning biblically to pay for and erase one's sins and transgressions, has it's roots in the primitive practice of, "scapegoating." An early barbaric piece of superstition in which the sins of a village were piled upon the unsuspecting shoulder's of an animal, often a goat, which was either sacrificed outright or driven from the village to die of the elements and lack of sustenance. By such an act the sins of the village were thought to be expatiated and assuredly to be followed by a better more blessed fortune. In examining whether the central tenet of Christianity is morally sound I will return to this example.
Versions of the Doctrine
The Christus Victor Version maintains that mankind was under the sinful influence of the devil reveling in sin and evil works. The devil's ownership over humanity can be traced back to the Adamic fall, or original sin. Christ frees us from this moral stricture by offering himself up as a kind of ransom. This is the oldest version of this dogma.
The Satisfaction and Penal Substitution version of this contends that only a human being can rightfully atone for the injury done to god's honor and justice incurred by Original Sin. Since this injury was done unto god by man only a god in mans' form, can propitiate god's wrath, thus Christ's incarnate form upon the Earth and subsequent torture and death is a sacrifice made by humanity to god in order to propitiation his wrath.
Hugo Grotius's Governmental Theory states plainly that god is ready to forgive and requires only a safe arrangement to demonstrate this forgiving attitude toward an infraction of his laws. By demonstrating what the price of disobedience is, god may forgive those who acknowledge this and repent. The substitutionary atonement is necessary to balance the scales of god's justice and set an example.
The Morality of Substitutionary Atonement
The morality of this doctrine may depend on your individual belief system. If Christ was the son of god, sent to expiate humanity's sins as part of a divine plan then you will probably find all other commentary to be superfluous.
But even the most staunchly religious must admit this is an odd and somewhat inelegant plan for redemption. Surely is god wished to forgive us our original sin (borne of the curiosity he supposedly endowed us with) he could simply do so without the pomp, circumstance, and sadistic torture of himself to himself. And if this was indeed the plan, what went wrong? Why must Christ come again and why is sin still present in the world. Surely god's plans are not subject to being thwarted.
To look at it from another point of view, is it moral to pile sin upon sin upon one being, torture and execute that being, and consider the moral slate wiped clean? Why history and literature are replete with Martyrs and people who have willingly paid for the crimes of another, in order to satisfy the childish notion of justice at work; If one person has suffered another must suffer in order to bring all back into balance.
But this idea, much like our poor goat being driven to his death, does not actually remove personal responsibility for sin or other wrongdoings. It is highly inhumane and immoral in that instance and does not appear any more moral by the light of theology. Surely one of the highest moral aspirations is that of taking responsibility for one's actions and one of the lowest is finding an eccentric Jewish preacher (or any other person) to take person responsibility for those sins. This would seem the ultimate abdication of personal accountability.
This dogmatic mechanism seeks to make us culpable in crimes before our very birth and offers reprieve only through Christianity. The best metaphor i can think to draw for this is giving birth to a baby addicted to opiates in utero and then a rather unscrupulous Doctor advocating keeping that individual on methadone for their entire life. They had no hand in the crime before they were born and yet must live with it's consequences and be totally indebted to a system into which they have been indoctrinated.
To square this with a sense of morality, even religious morality, seems to be casuistry of the worst kind.