The problem of evil can be stated in the following way.
(1) God is all powerful
(2) God is all good
(3) Yet evil exists
Unbelievers often say the existence of evil proves that Christianity is inconsistent and untrue. They state that if God was all powerful and all good then evil could not exist. But the Bible does teach that God is all powerful and all good while the existence of evil is a reality. If we add another statement we can remove the inconsistency found here.
(1) God is all powerful
(2) God is all good
(3) Evil Exists
(4) God has a morally sufficient reason for allowing evil
When we add statement 4 we now have the total picture of what the Bible actually teaches. The logical inconsistency is now removed. Christianity is consistent and true. We may not like this explanation but it is reality. We do not fully understand why evil exists because we do not see the entire picture as God does. We must trust God and realize that the existence of evil brings glory to God. There is a good reason for the existence of evil it has just not been fully revealed to us. The secret things belong to the LORD our God (Deuteronomy 29:29). A good example is the crucifixion of Christ. With the crucifixion a great evil was committed by men. But God brought about a greater good, namely the salvation of his people, which also brought him glory.
We must point out that the real problem of evil does not belong on Christians but on unbelievers. The unbeliever has no basis for anything even being good or evil in his worldview. He has no ultimate moral authority or standard by which to determine good and evil. The unbeliever could not be consistent with his worldview and even call murder or child abuse wrong. In order for the unbeliever to speak in terms of good and evil he must jump out of his own worldview and jump into the Christian worldview. He must borrow from Christianity in order to live his life and deal with reality.
The Christian has a basis for good and evil. The ultimate moral authority and standard is God and his Word. Good is that which is consistent with God's character and law. While evil is that which violates God's character and law. Unbelievers can offer no more than a mere opinion because they have no ultimate authority to which they can turn. If the unbeliever was consistent he could only say "so what?" to everything that happens.
Every time an unbeliever speaks of the problem of evil he actually proves the existence of God. He could not even talk about a problem of evil if God did not exist. When the unbeliever speaks of the logical inconsistency of Christianity he again proves the existence of God because there is no basis for logic without God. If God did not exist you would not be able to prove anything. You would be left with nothing more than absurdity.
The unbeliever cannot escape the fact that he is made in God's image and lives in God's world. In his heart of hearts he knows that the God of the Bible exists. The unbeliever simply suppresses the truth about God in unrighteousness. All unbelievers need to repent (have a change of mind) and trust in Christ alone for salvation. Then their minds will be renewed and they will be in line with reality.
Only Christianity provides the necessary preconditions for intelligibility. In other words only the Christian worldview makes sense of you world and fits reality. Christianity is true because of the impossibility of the contrary. All other worldviews are inconsistent, contradictory, and reduce to absurdity.