The problem of evil is a question in philosophy which asks how evil can exist alongside an all-benevolent, all-knowing, and all-powerful God.
This "problem" has issues. First of all, evil isn't made well-defined or even clear. Second of all, it juxtaposes evil with a specific, albeit common, perception of God. How is one supposed to answer a question practically made to lead to paradoxes? Start by asking some counter-questions, such as what evil is NOT.