Perhaps the greatest barrier to belief in God is the problem of suffering and evil. It is a difficult problem, and there are no easy answers.
This is the first in an ongoing series exploring the problem from a variety of voices within the Christian community. We will begin with a series of five presentations by Dr. William Lane Craig from his Defenders Class.
In an article elsewhere, Dr. Craig states,
“The problem of evil is certainly the greatest obstacle to belief in the existence of God. When I ponder both the extent and depth of suffering in the world, whether due to man’s inhumanity to man or to natural disasters, then I must confess that I find it hard to believe that God exists. No doubt many of you have felt the same way. Perhaps we should all become atheists.
But that’s a pretty big step to take. How can we be sure that God does not exist? Perhaps there’s a reason why God permits all the evil in the world. Perhaps it somehow all fits into the grand scheme of things, which we can only dimly discern, if at all. How do we know?
As a Christian theist, I’m persuaded that the problem of evil, terrible as it is, does not in the end constitute a disproof of the existence of God. On the contrary, in fact, I think that Christian theism is man’s last best hope of solving the problem of evil.” 
In the first lesson, Dr. Craig introduces the problem and distinguishes between the intellectual problem, in both the logical and probabilistic versions, and the emotional problem. The lesson is presented in a series of brief lectures with periods of Q&A interspersed. You can listen to the audio here or read the transcript here.
That you may know,Roger
 William Lane Craig, The Problem of Evil