Where evil came from (conclusion)
The law
     Being persons, Adam and Eve already had the potential to desire what was not theirs. However, that potential could not become actual apart from the law. Unless God said, “Do not eat from this tree,” sin could never enter their hearts.
Romans 7:8
     By standing against evil, God enabled it to enter. It could never exist unless he made a law against it.
     If we know why God made the law, we will know why he allowed evil, because the law made evil possible. Regarding this, the Bible brings up the surprising question, “Is the law evil?”
Romans 7:7
     The law is good. The law teaches us a higher good. It presents a challenge, an alternative for man to overcome. Norman Geisler said, “In this world, men are challenged to do good and noble things to overcome evil tendencies. That could not happen in a world without evil. The highest virtues and the greatest pleasures are impossible to achieve if there is no opposition as a precondition. Courage can only occur where there is a real fear of danger. Self-sacrifice is only noble where there is a need and an opposing selfishness to overcome.”
     Ironically, the commandment that enabled this higher good also arranged for evil to enter, but rather than hurting God’s sovereignty, evil proved it unstoppable. God wanted to reveal his justice and grace through opposition. He was already just and gracious. He is, was, and always will be. It was part of his character before evil entered the scene, but with evil God showed himself as Judge and Savior. 
     With evil, God would be a conqueror, taking back what is rightfully his and giving undeserved kindness to whomever he wished. It showed his holiness, his separateness, his above-it-all-ness. If I could explain it further, I would, but at some point I can go no further.
     Jesus said, “It is unavoidable that causes for stumbling should come, but woe to the one through whom they come.” It is inevitable for iniquity to enter the world, but woe to them who choose by their own free will to bring it in.
     Jesus also said that the one who is forgiven much will love God more. This aspect of love could not have shown itself without the law.
     The determining factor is the will of the one who gave us free will. It is his prerogative, his independent autonomous decision.
     Many people feel more cozy with a limited god who tried to stop evil and failed. I would rather be an atheist.
     Only the sovereign Lord who chose to allow evil can save us from it. If the limited god couldn’t prevent it the first time, there is no point at which he can save us. Only Jehovah can stomp out evil and never allow it to return.
     Many have denied God, because they wanted him to explain to their satisfaction the existence of evil and the suffering it brings. To them, I say, I understand how you feel, but we have no alternative. Only the one who allowed evil can eliminate it forever. If it depended on us at all, evil would continue indefinitely. 
     If we needed to know now, he would tell us now. We can either trust the one who knows and refuses to explain, or we can trust the one who does not even know. 
     With God in the picture, we at least understand the concept of “good.” If we remove God from the picture we cannot explain good, much less evil.
     Atheists have a dilemma. They cannot explain the existence of good or evil. We have no alternative but to believe in God.