The Problem of Evil: How could a good God create a world that contained evil?
Scripture addresses the problem of evil directly in the book of Job and delivers a key message: that God is trustworthy even when we don't understand him (Job 13:15), but it stops short of explaining the reason for evil's existence. Sadly, this response, and Isaiah's response that God's ways and thoughts are higher than ours (Isaiah 55:8-9), are not enough to answer the inquiring minds of seekers and skeptics. Thus, theodicies are developed, not to question God's sovereignty, but to try and know the mind of God (using our limited understanding) and hypothesize (like good science) why evil exists in the world.
First, one must realize that the existence of evil necessitates the existence of God. Like darkness, evil is a non-entity. It is definable only as the absence of something else. So just as darkness is the absence of light, evil is the absence of good. So what is good? Good is how close something fits with the absolute standard of perfection, a moral law. Without the standard, the terms good and evil become nonsensical, arbitrary terms comparing differences. However, in order for the standard to be absolute, transcending all times and cultures, it must be given by a moral law-giver, i.e. God. Thus, every time we recognize evil, we are acknowledging the moral law, and by extension confirming God's existence.
What is evil? Evil is the violation of purpose, the purpose of your creator and mine.1 As St. Augustine observed, everything God created was good and without evil. Since sin and evil are merely a privation of the good, evil itself has no nature. Moral evil arose because the will of angels and of men turned from the way in which they were created.2 So the real question is, for what purpose did God create us and why did he give us free will?
The best answer is love. Since God is eternally three persons, Father, Son and Holy Spirit, he has experienced perfect love for all eternity. So why create mankind? Marriage illustrates that a loving husband and wife wish to share their love and go on to create new life with which to share it. In this way, we can see God's desire to share his love by creating mankind. However, true love is choice not a feeling,3 so God chose to create mankind with free will. It's difficult to conceive of creatures capable of love when they have no option to do otherwise, without making puppets, robots, or slaves. For puppets only imitate the master's motions, robots follow preset commands, and slaves only obey out of fear – none of which qualify as love. However, it is the free will attribute of love that gives rise to evil, the result when the created chooses to not love God, violating their purpose. Thus, evil exists as a side-effect of love.
So God put forth the best possible world of all the possible worlds God could have created, a world of love. However, one that contained the possibility of evil in order to have a relationship with creatures capable of love. In choosing the best possible world, God obviously can conceive of evil, but he did not create it, declaring his creation good (Genesis 1). Sin and evil only entered into the world when man and angels chose to violate their purpose and not love God. Ultimately, God's perfect world would emerge, either immediately as humans choose to return God's love from the start preventing evil from ever entering the world, or after the fallen world has run its course and those who chose to love God in the face of evil are saved to love him for eternity.
Despite the creation of the best possible world, the reality of evil cannot alter the immutable characteristics of God. In his perfect holiness, no evil can stand. So, before the universe was created, Jesus Christ was sent into the world as an act of love to take sin and its evil effects upon himself and rescue his creations.4
Though God hates evil, he has enslaved it to serve his purposes. In our fallen world, God often sees evil in our development and journey toward perfection. Pain often works as God's megaphone to call man to mend his ways and to show him the truth.5 In fact, in order to understand why we sometimes see God use evil to bring about good, we must recognize that the universe was constructed with the purpose of loving God and making God known, not for the production of our happiness.6 However, a world devoid of all possibilities of suffering would be one without moral values, and especially the developed capacity to love.7
1 (Ravi Zacharias - The Mystery of Evil, The Sovereignty of Good)
2 (Sacramentum Mundi, 6:214)
3 (Gary Chapman, 5 Love Languages pg. 37)
4 (McGrath, 104)
5 (C.S.Lewis – The Problem of Pain)
6 (Hodge, 1:436)
7 John Hick (Evil and the God of Love)(360-361)