In my last post I mentioned the fact that certain key doctrines are decided or settled on or strengthened by the gospel. Some doctrines are the logical consequence of the gospel, a great example of this sort of doctrine is the doctrine of the Hypostatic Union: In Christ the fullness of deity and the fullness of human nature are united as one without mixing, without confusion, without one superseding the other. Christ is the union of divine and human nature.
This union forms the basis for the doctrine of the incarnation:
The doctrine of the incarnation holds that, at a time roughly two thousand years in the past, the second person of the trinity took on himself a distinct, fully human nature. As a result, he was a single person in full possession of two distinct natures, one human and one divine. (SEP)
So how exactly does this doctrine logically flow from the gospel? In Cur Deus Homo Anselm shows us how.
So what is the Gospel for Anselm? The Gospel for Anselm begins with an explanation of the end of man. Anselm believes that “human nature was created in order that hereafter the whole man, body and soul, should enjoy a blessed immortality” (112). He does not elaborate much on what this blessedness is supposed to be like, nevertheless, this is the sort of state for which God created humans, and this is the goal they were supposed to achieve.
However, something went wrong. Something prevented human beings from attaining this blessedness. What happened was that human beings sinned. Human beings have failed to render God his due. What God is due is all honor, glory, and praise, but human beings have turned in on themselves and have robbed God of these things. In order to attain blessedness for which they were created humans must not simply return what was taken away, they “must give back more than he (they) took away.” So it could be said that humans owe God a debt of honor… In order to be made right, humans must repay this debt of honor. However the satisfaction must be proportionate to the offense. The offence was infinite, so the repayment must be infinite. Humans are incapable of making this sort of payment, only God can make this sort of payment. On the flip side, only God is capable of making this payment, but only humans have the duty to make this payment. So the only solution would be that a God-Man makes satisfaction.
This is the gospel according to Anselm, that humans have dishonored God and owe him a debt which is impossible to repay by anyone besides someone who is fully God and fully human, thankfully the God-man repays the debt and acquires honor that is due to him but is given to the elect. So for Anselm his gospel hangs upon the incarnation, that there is someone who is a God-man.
Here is where the doctrine of the incarnation gets gospel centered:
In order for our atonement to count, the incarnation is necessary.
Without the incarnation, without the union of divine and human nature in the man Jesus Christ, there would be no gospel. So we can say that the gospel necessitates a doctrine of the incarnation.
CWoznicki Think Out Loud 