I guess the biggest thing that I learned from Lewis is that reality as we perceive it is such a small part of what is really happening. It's a recurring theme in most of his books.
In
Screwtape Letters, I learned that every action, every circumstance in my life, even something as small as a decision to eat lunch instead of pray, could be turned into a weapon for the Enemy if I'm not careful. There's a battle going on behind the scenes of daily life of which we are barely aware.
In
The Four Loves, Lewis talks about loving other people for what they could be rather than what they are. We need to see what God sees when He looks at them, rather than what we as mere humans can perceive on the outside of a person.
In
The Problem of Pain, Lewis explains that God uses pain to get our attention and to help us grow and mature and have empathy with others. There's a deeper purpose than we can see.
Those books and others woke me up to the fact that although things might look a mess on the outside, behind the scenes God has everything under control. And that is a comforting thought.
"My brain and this world don't fit each other, and there's an end of it!" - G.K. Chesterton