"For the Son of Man came not to be served but to serve, and to give his life a ransom for many.” Mark 10:45
The claim that Jesus of Nazareth, the incarnate Word of God, offered up his life for the salvation of mankind, lies at the very core of the New Testament message. In the Ancient Jewish mind, our predicament is that we are estranged from God, the supreme Good and source of all flourishing. The Jewish authors of the New Testament came to believe that the much-needed reconciliation with God -- what theological parlance refers to as atonement -- was achieved through the life, suffering and ultimate death of Jesus the Messiah.
How this is meant to work out has always been a matter of some controversy for Christians. Different 'theories of the atonement' have been proposed through the centuries, with varying degrees of success. It has recently dawned on me that contemporary Christians, in their thinking and speaking about the atonement, unknowingly fluctuate between two distinct theories thereof: penal substitution theory on one hand, and satisfaction theory on the other.
Let us briefly go through each in turn. Penal substitution theory starts with the assumption that humanity's turning away from God is deserving of a just and severe condemnation. God, in his infinite mercy, longs to forgive and reconcile humanity to himself. But in his infinite righteousness, he cannot let this great sin go unpunished. This inner tension within God's character is resolved through the cross, on which Christ bears the required condemnation in our stead, thereby becoming our substitute. As some Christians like to put it, God, rather than meting out punishment onto us, took the punishment onto himself, out of love.
When Christians speak of Jesus 'taking the punishment for our sins' or 'bearing the wrath of God', they are (consciously or not) drawing from the resources of penal substitution theory. This reliance comes out most clearly when they draw an analogy with a judge who sentences a criminal, before paying the penalty himself.
The fully-developed penal substitution model seems to have originated with the Protestant Reformers, though I'm told that there are antecedents in Augustine. For a more recent, classic defense of the theory, see John Stott's The Cross of Christ.
Satisfaction theory is subtly different. Here again, humanity's collective turning away from God is the theory's starting point. But here, the focus is not on punishment, but on repentance. It is taken for granted that the appropriate response to serious personal sin is an attitude of repentance, which involves both deep regret and a sincere 'turning around' of one's life towards the good. Unfortunately, given our condition, any repentance we try to offer will be woefully inadequate. Thankfully, Christ, by living a life of sheer sacrificial love for God and human beings, carried out the perfect repentance that we couldn't. He repented on our behalf, thereby achieving atonement. When Christians speak of Jesus 'paying our debt, which we couldn't pay', thereby releasing us from such a debt, they are (consciously or not) drawing from the resources of satisfaction theory. Notice that, as with penal substitution, Christ becomes our 'substitute' in some sense. But he does not become our penal substitute, since he does not take on the penalty that our estrangement from God deserves. Rather, he takes on the repentance that we owe, but cannot give. The satisfaction models seems to have been preferred by medieval theologians, most notably Anselm and Aquinas. For a more recent (and very illuminating) defense, see Richard Swinburne's Responsibility and Atonement.
I have mentioned analogies and manners of speaking which Christians use to explain the atonement, and which, as we have seen, draw on either of penal substitution or satisfaction theory. What I find very interesting is that, often, the same individual Christian will draw on both models at the same time, probably without realizing it. Here's a fun exercise: try asking a Christian to explain the atonement. If she speaks of Christ taking on the 'punishment' that we deserve, she is relying on the penal substitution model. If she speaks of Christ as paying our 'debt', she is likely relying on the satisfaction model. In my experience, many Christians are happy to use both characterizations simultaneously.
To some extent, this is a problem. While one may perhaps accept some elements of each theory, they are not fully compatible. I don't think Christ can both be the willing recipient of the condemnation we deserve, and the author of the repentance we couldn't achieve. These two pictures are very different. Even so, one could try to accept both, while ascribing primacy to the one of them. One way to do this would be to consider one of the models as a literally true (though, as is necessarily the case in theology, incomplete) representation of the atonement, and the other as a useful metaphor. This is the approach I take. I believe that the satisfaction model should have primacy over the penal substitution model. More precisely, I believe that it is literally true that Christ is the author of the repentance we couldn't achieve (this obviously shouldn't be taken to mean that the theory is flawless or complete). In contrast, in my view, Christ took on the punishment we deserved only in a metaphorical sense. Strictly speaking, he did not, he was not condemned in our place. But he certainly did pay the cost of our alienation from God, and this involved great suffering. In that sense, he was 'punished' for what humanity did, though this is a metaphorical sense of the term 'punished'. I will finish with some indications of why, in my opinion, the satisfaction model is the more biblically plausible candidate as an account of the atonement:
1. It demonstrates a better understanding of the Old Testament sacrificial system: time and time again, the New Testament authors liken Christ to a 'sacrificial lamb', referring to the Ancient Jewish practice of sacrificing animals for the purposes of atonement. Hence, for penal substitution theorists, the significance of such sacrifices is that the animal is punished in stead of the offender, fulfilling the demands of justice. But this interpretation seems inaccurate, since, in the sacrificial system, flour could be offered as a means of atonement (Lev 5.11). Surely, the Ancient Jews did not think that the flour was being condemned in our stead! It seems more reasonable to say that the offering of a sacrificial gift was a way of expressing repentance. But if that's right, then the NT authors' characterization of Jesus as a 'sacrificial lamb' fits much better with the satisfaction model, in which Christ's offering of his very life achieves the repentance we couldn't achieve. 2. It explains the relevance of Jesus' life, rather than simply his death, to atonement: it is very important to the NT authors that Jesus lived a morally excellent life, being a 'lamb without blemish' (Heb 9:14, 2 Cor. 5:21, 1 Pet 1:19). This is easily explained in the satisfaction model: Christ's entire life, from the moment he was born to his dying breath, was a life of unparalleled love and grace, and hence a supreme act of repentance, on our behalf. Had it instead been a life of selfishness, it would obviously have fallen short of that. In contrast, the penal substitution model doesn't have the resources to explain this. If the problem is that there must be a punishment for sin, it is entirely unclear why a morally excellent individual (as opposed to, say, Donald Trump) must undergo said punishment in order to meet the rigors of justice. 3. Is it really the same punishment? The New Testament teaches that the punishment of the unrepentant is " eternal destruction, [being] separated from the presence of the Lord" (2 Thess 1:9). Penal substitution theorists argue that Christ experienced this while nailed to the cross, which, to them, explains his cry of despair, " My God, my God, why have you forsaken me?" (Mt. 27:46). The obvious problem here is that if Christ was indeed separated from God at that moment, this separation came to an end. In that case, how he could have taken our punishment is hardly intelligible.