I preached today, calling Christians to boast in weaknesses because we know that Christ’s power is magnified in us when we are weak (2 Cor. 12:1-10). Recognizably, this is a hard message to apply because weaknesses – in the form of hardship and suffering – often lead people to doubt God rather than thank God.
In Tim Keller’s The Reason for God, he has a chapter responding to the question, “How could a good God allow suffering?” In it he describes how C. S. Lewis originally rejected the idea of God because of the problem of suffering but then came to realize that it was even more problematic for atheists. Lewis came to see that suffering in the world was actually evidence for the existence of God. Lewis writes in Mere Christianity,
My argument against God was that the universe seemed so cruel and unjust. But how had I got this idea of “just” and “unjust”? . . . What was I comparing this universe with when I called it unjust? . . . Of course I could have given up my idea of justice by saying it was nothing but a private idea of my own. But if I did that, then my argument against God collapsed too – for the argument depended on saying that the world was really unjust, not simply that it did not happen to please my private fancies . . . . Consequently atheism turns out to be too simple.
Keller goes on to write, “Lewis recognized that modern objections to God are based on a sense of fair play and justice . . . . If you are sure that this natural world is unjust and filled with evil, you are assuming the reality of some extra-natural (or supernatural) standard by which to make your judgment.”
The fact that we even recognize suffering as a problem already suggests that there exists a God – one who gave all people an innate sense of moral judgment. But even if we acknowledge this fact, boasting in our weakness (in the suffering we experience) is still not easy. We need God to do a supernatural work in our hearts, but at least we can know that God exists to do just that.

[...] So if the problem of evil and suffering bothers you, that just demonstrates that there is an innate sense of morality (good/bad, just/unjust) that God has placed inside you (Romans 2:15). This same point was made in a previous post: Suffering as Evidence for God. [...]