Miracles that I was tempted to give up. But when I saw that Chapter 14 was on the Grand Miracle (the incarnation), I knew I had to hang on. Everyone knows the famous quote, We believe the sun is in the sky at midday in summer not because we can clearly see the sun, but because we can see everything else. But its context is the incarnation. To Lewis, God's act of becoming man is the light that clarifies all other Christian doctrines.
In the first half of the book Lewis argues for the naturalness of miracles. Contrary to popular opinion, they do not go against natural laws, but confirm them. If the laws of Nature are necessary truths, no miracle can break them: but no miracle need break them. It is with them as with the laws of arithmetic. If I put six pennies in a drawer on Monday and six more on Tuesday, the laws decree that - other things being equal - I shall find twelve pennies on Wednesday. But if the drawer has been robbed, I may in fact only find two. Something will have been broken (the lock of the drawer or the laws of England) but the laws of arithmetic will not have been broken....
We are in the habit of talking as if the laws of Nature caused events to happen; but they never caused any event at all. The laws of motion do not set billiard balls moving: they analyze the motion after something else has provided it. They produce no events; they state the pattern to which every event must conform. Thus in one sense the laws of Nature cover the whole field of space and time; in another, what they leave out is precisely the whole, real universe - the incessant torrent of actual events which make up true history.... A miracle is emphatically not an event without cause or without results, Its cause is the activity of God; its results follow according to Natural law.
On the necessity of the incarnation: In the Christian story God descends to re-ascend. He comes down; down from the heights of absolute being into time and space, down into humanity; down further still, if embryologists are right, to recapitulate in the womb ancient and pre-human phases of life; down to the very roots and sea-bed of the Nature He has created. But He goes down to come up again and bring the whole ruined world up with Him.
On Christ's death: On the one hand Death is the triumph of Satan, the punishment of the Fall, and the last enemy. On the other hand, only he who loses his life will save it. We are baptized into the death of Christ, and it is the remedy for the Fall. Death is, in fact, ambivalent. It is Satan's greatest weapon and also God's great weapon; it is holy and unholy, our supreme disgrace and our only hope, the thing Christ came to conquer and the means by which He conquered.
Lewis also addresses the important topics of prayer, free will vs. God's sovereignty (always a mind bender), death/rebirth and the spiritual vs. the material. I loved his quirky phrase for the idea that all reality is found in Christ: He is ultimate Fact-hood. This was a difficult but extremely worthwhile book for building mental and spiritual muscle.