God was, in the pre-existent fellowship of the Trinity, completely and perfectly satisfied, overflowing with pleasure and joy. God considered it a great good to share the joy and satisfaction he had in himself with others—with humankind—creatures he made for that very purpose. So in creation, after making everything in the universe to foster life—both lower and higher forms for the ultimate support of human life—God finally made human beings in his in his image, giving them the capacity to know him and experience the joy and satisfaction he has in himself.
He must have determined that for his overwhelming joy and satisfaction to be experienced by humanity, there must be sin and suffering. How do I come to this conclusion?
First, the existence of actual sin and evil was necessary for God to define himself to his creatures. He defined himself to them as holy (morally good), which requires that both moral good and evil must be defined. God spelled out both reward for good (vis. pleasure) and consequences for evil (vis. suffering), which are also tied to being like or unlike his character. Just as to understand light one needs to know what darkness is, evil and suffering stand in stark contrast to good and pleasure.
Second, sin was made possible when God granted humans a free will. Free will is necessary for true love to occur. C.S. Lewis wrote:
...free will, though it makes evil possible, is also the only thing that makes possible any love or goodness or joy worth having. A world of automata—of creatures that worked like machines—would hardly be worth creating. The happiness which God designs for His higher creatures is the happiness of being freely, voluntarily united to Him and to each other…. And for that they must be free.
Without a morally significant free will, our “goodness” (or obedience to a good God) means nothing and is not praiseworthy, any more than it is praiseworthy for a machine to do what it was designed to do. Likewise, if it were impossible to not choose good (or to not choose at all), “badness” (or, disobedience to a good God) is without meaning and God would be unjust to punish it. Instead failure to do good would be a design flaw, which might point to an inept or corrupt designer (God). Therefore, Adam and Eve were created free in the truest sense. Since they were truly free moral agents, they were responsible for their actions. They sinned, and the consequences affected the world and all people who descended from them. All humans born since the fall are sinful, blind, and are “dead in our trespasses” (Eph. 2:5, Col. 2:13).
Unlike Adam, who was previously untainted by sin, our tendency is already toward sin. Therefore, we must be drawn by God and given the ability to see his light/goodness/beauty. Then we are “made alive” by his grace and in response to his love. This results in new birth and the ability to understand and desire good for God’s glory, and experience the joy that God gives (in shadows now while we still live in this world, and fully when our salvation is one day realized in heaven).
Third, sin made it possible for God to show himself more fully to his fallen creatures (humans) who were originally created with the capacity to know him. Without sin, we never would have known some most important aspects of God’s character: his grace, forgiveness, longsuffering, sacrificial love, and mercy. Indeed we would have never known Christ or had need of him. Therefore, the second person of the Trinity and/or his nature would have remained a mystery and we would have never needed his presence with us as Emmanuel and Savior.
Finally, sin and suffering must be viewed in perspective of the exceeding great joy God has in store for those who he has called in heaven. This is a joy that, by comparison, FAR outweighs the pain we experience on this side of eternity. The greatest suffering we experience here will be a faint memory for us in heaven—if, that is, we can remember it at all. Even in this world we experience this phenomenon in a much less-significant way, as in the case of women who endure the pain of pregnancy and childbirth (part of the curse after the fall) soon forget it at the sight of their new baby.
There are even more ways that God uses pain in our lives. As a perfect Father, he grows us and makes us more like Christ as we “share his sufferings.” He reveals himself to us as we seek him and rely on him. He corrects us, heals us, comforts us, and uses us to bless others. Am I saying that suffering is good, and by extension, that sin is good? No. Not in themselves. But as they drive us—flawed people in a fallen world—toward God who allowed them to occur, even they can be used for his glory and our good; both here and in heaven. In this way, “there is beauty in the fall of man.”