How does a Christian reconcile the fact of evil and suffering in the world in the face of a God that is omnipotent, omniscient and benevolent? If he is omnipotent then he knows about all evil before it occurs so why does he allow it? Surely if god is omnipotent then he can halt evil. If he is benevolent then why will not act against it?
Marc raised the same question in the comments section of, Good Friday: Why Celebrate Easter? In the discussion that followed I charged him with special pleading, of holding Christians to a higher standard than the standard he tacitly holds skepticism to. As discussions in comments sections are often missed instead of continuing the debate with Marc I thought I would express myself more clearly here. In doing so I will borrow extensively from a talk Matt gave for the launch of Thinking Matters (which you will see when we finally get the video footage of the talk online). [Given the difficulties of footnoting notes and impressions from talks and knowledge obtained through years of discussions with one's spouse (though some came from primary sources that I read myself) pretty much from this post from this point onwards, though not in entirety, should be seen as being authored by MandM as opposed to just me though it is posted by me because overall it I put it together.]
Before addressing an objection of this nature one should first establish the correct approach to take towards addressing criticisms of the faith and be clear as to what constitutes a fair set of rules for the terms of engagement. Timothy Keller writes,
All doubts, however sceptical and cynical they may seem, are really a set of alternate beliefs. You cannot doubt belief A except from a position of faith in belief B….
The only way to doubt Christianity rightly and fairly is to discern the alternative belief under each of your doubts and then ask yourself what reasons you have for believing it. How do you know your belief is true? It would be inconsistent to require more justification for Christian belief than you do for your own, but that is frequently what happens.
In fairness you must doubt your doubts. My thesis is that if you come to recognise the beliefs on which your doubts about Christianity are based, and if you seek as much proof for those beliefs as you seek from Christians for theirs - you will discover that your doubts are not as solid as they first appeared.
When one encounters a charge like the one Marc raised, I understand that even if Marc didn’t set the problem out in the manner the world’s top atheist philosophers might have done, his question nevertheless hides a disguised argument that warrants addressing. Daniel Howard-Snyder states,
[T]he theoretical "problem" of evil is often expressed in the form of a pointed question. God is able to prevent evil and suffering and He would know about them before they happened, right? Moreover, since He is unsurpassably good, surely He would not permit them just for the fun of it. So why doesn’t He prevent them?
 That as God is omniscient and omnipotent (all-knowing and all-powerful) he would be both able to know about all the suffering that exists and act to prevent it;
 Given that God is good, he would not allow such evil to exist unless he had a good reason for it.
These premises entail that if God exists then he must have a good reason for allowing suffering. I agree with Marc and those who have gone before him on this part of their objection, I am sure that God does had a good reason. However, the question that follows from here, which is typically “then, what is God’s reason for allowing suffering?” which I concede has powerful rhetorical force, contains a critical flaw.
If one is to look at the question purely rationally it is should become apparent. This flaw is widely noted and discussed in the literature by the likes of Steve Wykstra, Alvin Plantinga, Peter Van Ingwagen, William Rowe, Micheal Tooley, William Alston, and Howard-Snyder to name a few.
So what is this flaw? I have not contested the claim that if God exists then he must have a good reason for allowing evil. However this has not satisfied Marc who wants to know what that reason is. Asking this latter question tacitly attempts to add a further premise to the above argument,
 If a Christian cannot provide a detailed account of God’s reasons in  then it follows that God has none.
Alvin Plantinga provides an illustration of the flaws inherent in . Paraphrasing him; suppose I ask you too look in a tent and tell me if there's a St Bernard inside. In this instance, I would have every reason to trust what you say you see as a St Bernard the sort of thing I would expect you to be able to observe if it were inside a tent. But suppose I ask you to look inside and tell me if there are any 'no-see-ums' inside the tent (a no-see-um is gnat with a big bite that is small enough to pass through the netting of a tent, as such it is too small to see). Now, I have no reason to trust your answer in this instance, as you can't see no-see-ums. Here's the problem; the sceptic is assuming that if there is a reason for our suffering then it is more like a St Bernard than it is like a no-see-um. However, this is simply assumed, not argued for. It is certainly, if not at least possible, that we suffer for a reason but that that reason may not be something that we can easily detect.
For the problem of evil to succeed the sceptic must provide some argument as to why God’s detailed reasons for allowing evil are like St Bernards and such an argument must be grounded on premises that Christians are rationally required to accept or else we could simply escape the charge by justifiably rejecting the premise.
Now if a finite human being, such as myself, with limited factual knowledge, limited perspective in time and space and an imperfect moral character cannot produce a good reason as to why evil occurs then I fail to see why the Christian must accept the conclusion: ‘therefore, God cannot possibly have any such reasons.’
William Alston has noted that the sceptic argument in this context is a bit like a person who, with no background in quantum physics, decided that when he failed to understand why the world’s best physicist held a particular view that if followed that the physicist obviously had no reason to hold it.
Suppose I am wrong. Suppose that the failure to provide an answer does mean that it is improbable that one exists and from this, that it follows the existence of God is improbable given the existence of evil. What follows from this? Nowhere near as much as you might think because the fact that the existence of God is improbable on one fact does not mean that it is improbable per se.
Plantinga notes that there are many beliefs that we hold to which are improbable on some body of evidence we believe. If I was playing poker was dealt four aces, then this is highly improbable given the number of cards in the pack and number of possible combinations that I could have been dealt. Yet I am rational in believing that I was dealt four aces as I can see that I have four aces in my hand (to give but one defence).
Moreover, it is well known that a belief can be improbable on one sub-set of beliefs a person possesses and yet highly probable by every thing that the person believes. For example, if I know my friend is French and I know that most French people cannot swim then my belief that my friend is a swimmer is improbable based on this set of evidence. On the other hand, suppose I know that my friend is a life guard by profession and that all life guards, even French ones, can swim. Then despite the fact that a belief is improbable on the basis of one set of evidence, it is not necessarily improbable on the whole.
Finally the question needs to be raised about how well Christianity performs regarding the existence of evil relative to alternative views. Some Philosophers have suggested that the existence of evil might also make the non-existence of God impossible. I can only sketch the reasons briefly but they are worth noting.
First, in order for suffering to exist sentient life forms must exist. However, there have been various discoveries from contemporary physics which establish that a universe evolving life is extremely improbable. For life to evolve there are around 15 constants necessary, each must have precise values and if they were off by a million or even one in a million, life could not evolve. Even if some of these constants had differed by 1 in 10 to the power of 60 then life could not evolve.
Second, some of the worst forms of evil involve human cruelty and evil but in order to identify these things as such this requires the existence of moral principles or rules that prohibit this kind of conduct and deem them as cruel or evil. Now one question that can be raised by many in the literature, William Lane Craig and J.L. Mackie spring to mind, is whether the existence of objective moral principles is likely on an atheistic view of the world.
Is it likely that in a universe composed entirely of matter and energy that objective principles or rules could come into existence independently of any mind? Many people find this a puzzling question. My point is not to endorse (or reject) these lines of inquiry; it is simply to show that it is not obvious that the typical sceptical view is any more defensible given the existence of evil than belief in God is and more work would need to be done by the sceptic to show that it is.
So my response to the problem of evil then is three fold. The objection relies on an assumption that is false or at any rate, an assumption that no reason is forthcoming as to why a Christian should accept it. Further, even if evil does make the existence of God improbable one would need further argument to show that this meant Christianity was irrational. Finally, even if the sceptic could do this it the problem of the mirror remains, one would need to show that the alternatives to Christianity, such as skepticism, were better able to account for the existence of evil. As none of these criteria have been met, I remain a Christian.
 Timothy Keller Reason For God: Belief in an Age of Skepticism (New York: Dutton, 2008) xvii-xviii.
 Daniel Howard-Snyder “God, Evil, and Suffering” in Reason for the Hope Within (Eerdmans 1999), ed. Michael J. Murray, 3, http://www.ac.wwu.edu/~howardd/god,evil,andsuffering.pdf.
 Ibid, 4.
 Alvin Plantinga Warranted Christian Belief (Oxford University Press: 2000) 466.
 Keller Reason for God xvii-xviii.
 William Alston "Some Temporary Final Thoughts on Evidential Arguments from Evil" in The Evidential Argument from Evil ed Daniel Howard-Snyder (Bloomington Indianapolis, Indiana University Press: 1996) 317.
 Francis S. Collins The Language of God: A scientist Presents Evidence for the Existence of God (Free Press, 2006) 75.