If God Is Good, Why Is There So Much Evil in the World?
Evil in the world would not be possible if God had not given people "free will". God does not control people's choices. He knows what each person will choose, but he doesn't make them or cause them to choose it. Each person chooses to behave for the good of society or to behave selfishly to the detriment of society.
God created Angels with free will also. God did not create evil. When He created beings with free will, He created the possibility for evil to come into existence. Free beings choosing to treat each other with hate and selfishness instead of love and caring are what creates evil in the world. The first being to choose pride instead of love was an Angel who was originally named Lucifer. It may sound like a fairy-tale, but he is described in the Bible as having so much pride in his own beauty that he wanted to be worshipped as God. He and one-third of all the Angels in Heaven started a rebellion and were cast down to the Earth. After that, Lucifer's name was changed to Satan and the Angels that went with him are called demons. To get back at God for doing this, Satan became mankind's adversary and accuser and he has an organized army of demons doing his bidding daily. They are the ones responsible for much of the evil in the world, and they especially target Christians.
Evil implies a standard of morality. If a good God did not exist, where would that standard of good and evil come from? If morality actually evolved to enable people to live cooperatively in groups, then why is there still so much evil in the world? It seems there is a need for a moral standard to exist, so that everyone can count on it to be beneficial and absolutely just. A standard like that would need to be super-human, so humanity would need to look outside itself to see if such a standard exists.
For a more in-depth study of this subject please visit: Evil in the World.