Here's the famous Problem of Evil. The following three propositions can not all be true: God is omnipotent; God is wholly good; and evil exists.
It is very fun to read the historical debates. To make it even more chaotic, I'd like to add some of my own thoughts.
First, the debate on the Problem of Evil is of little practical significance to most people. No matter who wins the argument (temporarily), it does not change anything. It does not bring us anywhere.
Second, the line between Good and Evil is never clear. What seems good to you might seem evil to him. We can hardly find anything that is regarded as evil by all people.
Actually, in the nature, things simply happens. Grass grow, lambs eats grass, lions kill the lambs, and when the lion dies, its body becomes fertilizer for the grass. There's no "good or evil", no mercy or cruelty. It just happens.
So, if they don't exist, then why do we feel Good and Evil so strongly?
Good and evil are notions created by human. For example, a storm kills people. It is just a part of natural and physical laws: storms are formed, things are destroyed. We think it is evil because we sympathize with the dead and their family. Why do we have sympathy for them? Because we don't want to lose our beloved ones. It is human nature. So, Good and Evil arise when the Law of the World hits human nature in the face. We human are roots of both Good and Evil.
Third, God itself is a human fantasy. This will be another topic later.
So, as I see it, neither God nor Good/Evil exists. Therefore the Problem of Evil is not a problem. It is for training purpose only, or for fun, if your belly is full.