Greg Koukl has written a noteworthy argument for the existence of God through the reality of evil. The existence of evil has probably been the most difficult obstacle in my personal belief. However, the existence of evil is not a good argument against the existence of God. I hear this argument by atheists frequently.
Below is a taste of what Greg writes about in the article:
The argument against God based on the problem of evil can only be raised if some form of moral objectivism is true. Morals, therefore, exist. I need not give a complete taxonomy of ethical guidelines to make my case. If there is even one moral absolute, it invites the question, "What kind of world view explains the existence of this moral rule?"I think this brings challenges to not just atheists but to theists. If evil exists—God exits. However, which world view has the best explanation for this? I side with Christianity, but Christians have a lot “splannen” to do with some of the things in the OT and historical events in the world. Nevertheless, I think it can be done, but there is no “silver bullet” for the problem of evil (though I wish there was).