Part 1 here.
Several times through my year with cancer I asked myself, “Was the growth I experienced in my trust and love for God worth all that I went through? Put another way, if God had said to me, “Mark, this year I am going to move you to greater understanding of who I am, greater maturity, greater dependency upon me, and as a result, a more meaningful worship of me, but it is going to cost cancer and two surgeries and a brain tumor,” would I have accepted God’s offer or would I have said, “No thanks, God, I am content where I am. Suffering those things is not worth knowing you more and experiencing you as the God who heals and the God who will never leave me or forsake me.” I’m afraid I would have made the latter choice.
Believing that the suffering God sovereignly ordains for my life is necessary is easier to believe than that it is good. There are many necessary difficulties in life—getting an annual checkup, flossing, getting a flu shot—but we typically don’t think of these as good. God does not think in terms of necessities, however. What he intends for you is your eternal good. He means to maximize your joy for all eternity, and your suffering in this life is a key part of that plan.
Paul reminds us that we cannot even comprehend the glory God is preparing for us. “But, as it is written, ‘what no eye has seen, nor ear heard, nor the heart of man imagined, what God has prepared for those who love him’” (1 Corinthians 2:9).
Yet, this glory is not just an eternal destiny to which we look forward; it begins now, in this life. Lewis again:
“Imagine yourself as a living house. God comes in to rebuild that house. At first, perhaps, you can understand what He is doing. He is getting the drains right and stopping the leaks in the roof and so on; you knew that those jobs needed doing and so you are not surprised. But presently He starts knocking the house about in a way that hurts abominably and does not seem to make any sense. What on earth is He up to? The explanation is that He is building quite a different house from the one you thought of – throwing out a new wing here, putting on an extra floor there, running up towers, making courtyards. You thought you were being made into a decent little cottage: but He is building a palace. He intends to come and live in it Himself.”
All this reminds us that our usual concept of good—anything that does not disturb our comfort and that helps us further on our way to achieving paradise in this life—is seriously lacking. Many of us would be content for happiness and ease now, even if that meant the forfeiture of joy and rest eternally. Such an idea is the antithesis of Jesus words that it is no benefit whatsoever to gain the whole world and lose one’s soul.
 C. S> Lewis, Mere Christianity.