In Part 1 Lewis showed how the Incarnation was a pattern that was repeated throughout Nature. In Part 2 he showed the similarity of the Christian story to other Pagan stories of dying and rising gods, yet noticed how out of place the story of Jesus is among the pagan stories. In Part 3 Lewis will begin to offer an explanation for the incongruity. From chapter 14, "The Grand Miracle," from Miracles; a Preliminary Study:
There is, however, one hypothesis which if accepted, makes everything easy and coherent. The Christians are not claiming that simply 'God' was incarnate in Jesus. They are claiming that the one true God is He whom the Jews worshipped as Jahweh, and that it is He who has descended. Now the double character of Jahweh is this. On the one hand He is the God of Nature, her glad Creator. It is He who sends rain into the furrows till the valleys stand so thick with corn that they laugh and sing. The trees of the wood rejoice before Him and His voice causes the wild deer to bring forth their young. He is the God of wheat and wine and oil. In that respect He is constantly doing all the things that Nature Gods do: He is Bacchus, Venus, Ceres all rolled into one. There is no trace in Judaism of the idea found in some pessimistic and Pantheistic religions that Nature is some kind of illusion or disaster, that finite existence is in itself an evil and that the cure lies in the relapse of all things into God. Compared with such anti-natural conceptions Jahweh might almost be mistaken for a Nature God.
On the other hand, Jahweh is clearly not a Nature-God. He does not die and come to life each year as a true Corn-king should. He may give wine and fertility, but must not be worshipped with Bacchanalian or aphrodisiac rites. He is not the soul of Nature nor of any high and holy place: heaven is His throne, not His vehicle, earth is His footstool, not His vesture. One day He will dismantle both and make a new heaven and earth. He is not to be identified even with the 'divine spark' in man. He is 'God and not man': His thoughts are not our thoughts: all our righteousness is filthy rags....
Jahweh is neither the soul of Nature nor her enemy. She is neither His body nor a declension and falling away from Him. She is His creature. He is not a nature-God, but the God of Nature -- her inventor, maker, owner, and controller. To everyone who reads this book the conception has been familiar from childhood, we therefore easily think it is the most ordinary conception in the world. 'If people are going to believe in a God at all,' we ask, 'what other kind would they believe in?' But the answer of history is, 'Almost any other kind.' We mistake our priveleges for our instincts: just as one meets ladies who believe their own refined manners to be natural to them. They don't remember being taught.