I have been in considerable trouble over the present danger of war. Twice in one life--and then to find how little I have grown in fortitude despite my conversion. It has done me a lot of good by making me realise how much of my happiness secretly depended on the tacit assumption of at least tolerable conditions for the body: and I see more clearly, I think, the necessity (if one may so put it) which God is under of allowing us to be afflicted--so few of us will really rest all on Him if He leaves us any other support.Later that year Lewis returned to this theme in writing Owen Barfield:
I had so often told myself that my friends and books and even brains were not given me to keep: that I must teach myself at bottom to care for something else more (and also of course to care for them more but in a different way) and I was horrified to find how cold the idea of really losing them struck. An awful symptom is that part of oneself still regards troubles as 'interruptions' as if (ludicrous idea) the happy bustle of one's personal interests was our real work, instead of the opposite.--The Collected Letters of C. S. Lewis, Vol. 2 (Cambridge: Cambridge University Press, 2004), 225-26, 231-32
I did in the end see (I dare not say 'feel') that since nothing but these forcible shakings will cure us of our worldliness, we have at bottom reason to be thankful for them. We force God to surgical treatment: we won't (mentally) diet.