In the doctrine of the atonement we see perhaps the clearest indication of the organic character of theology, that is, we see that the various doctrines fit together in a cohesive fashion. The position taken on any one of them affects or contributes to the construction of the others. Here the doctrines of God, humanity, sin, and the person of Christ come together to define the human need and the provision that had to be made for that need. And from our undestanding of these other doctrines issues our understanding of the various facets of salvation: our being given a righteous standing in God’s sight (justification); the instilling of spiritual vitality and direction into our lives (regeneration); the development of godliness (sanctification). Theology, when properly done, possesses an aesthetic quality. There is an impressive symmetry or balance among the different facets of doctrine. There is an interconnectedness reminding us of the beauty of a smoothly functioning machine, or of a painting where each color complements the others, and the lines and shapes are in correct and pleasing proportion to the remainder of the picture.
Our doctrines of God and of Christ will color our understanding of the atonement. For if God is a very holy, righteous, and demanding being, then humans will not be able to satisfy him easily, and it is quite likely that something will have to be done on humans’ behalf to satisfy God. If, on the other hand, God is an indulgent, permissive Father who says, “We have to allow humans to have a little fun sometimes,” then it may be sufficient simply to give them a little encouragement and instruction. If Christ is merely a human being, then the work that he did serves only as an example; he was not able to offer anything on our behalf beyond his perfect example of doing everything he was required to do, including dying on the cross. If, however, he is God, his work for us went immeasurably beyond what we are able to do for ourselves; he served not only as an example but as a sacrifice for us. The doctrine of humanity, broadly defined to include the doctrine of sin, also affects the picture. If humans are basically spiritually intact, they probably can, with a bit of effort, fulfill what God wants of them. Thus, instruction, inspiration, and motivation constitute what humans need and hence the essence of the atonement. If, however, humanity is totally depraved and consequently unable to do what is right no matter how much they wish to or how hard they try, then a more radical work had to be done on their behalf.
Millard Erickson, Christian Theology, p. 799-800