Christian apologist J.P. Moreland once wrote (paraphrased): "The origin of evil is a problem that Christianity creates, yet it is a problem often attempted to be solved by atheists, who never needed to solve it in the first place."

Christianity declares there exist such things as "good" and "evil," it defines these concepts in relation to God, the ultimate "good" standard. But if God existed for all eternity and created a "very good" universe, whence came evil? (This is a theodicy for people who like big words like me.) It's a difficult subject that only Christianity creates for itself, and many Christian theologians work hard at solving.

Atheists, on the other hand, do not need to acknowledge the existence of any "good" or "evil." If we are just glorified hydrogen atoms from the Big Bang, then such concepts are nonsensical, just as it would be nonsensical to say it was wrong for one bacteria to eat another, or it was wrong for one rock to fall on another rock. Yet nearly all atheist philosophers seem compelled to tackle the very difficult problem of evil! Why in their right mind would they want to do so?

Christian apologist Ravi Zacharias once said that a good measure of a worldview is it's ability to explain other worldviews that are different or contradictory to it. Atheists attempt to reason why Christians behave the way they do (selfish genes, communal contracts, etc.). In my opinion they are lackluster. Christianity, however, explains very well the seemingly-incomprehensible actions of atheists:

Christianity says that, deep down, atheists understand the concepts of "good" and "evil" because they are written on their heart. Struggling to "explain away" this clear evidence of God, atheists seek to solve the problem of evil, but in so doing, reveal the truth of the scripture I quoted above.