It is Job's contention that, of all that has happened to him, the hand of the Lord has done it all. Job believed that God holds the breath of every living thing in His hand and all that happens, good or evil, comes from His hand.
It strikes me odd that neither Job nor his friends ever attribute anything to the working of the devil. Even though Satan had a significant role in Job's suffering from the very beginning, Job nor his friends perceived Satan's hand in Job's sufferings. To Job, good and evil were both from the hand of the Lord, and God doesn't have to have a good reason for either. To Job's friends, good was God's reward for the righteous and evil was God's reward for the sinner.
To be sure, God is sovereign and does as He pleases. "He makes the nations great, then destroys them; He enlarges the nations, then leads them away." (Job 12:23) God does appoint the rise and fall of nations, this is true. "Behold, He restrains the waters, and they dry up; and He sends them out, and they inundate the earth." (Job 12:15) This is also true, God does send famines and floods, but the question remains, are all famines and floods the direct work of God's hand? The insurance industry refresh to natural disasters as "acts of God", but is this fair to God? I believe that most meteorological and geologic disasters are simply the after shocks of Noah's flood. Noah's flood permanently changed the earths weather patterns. Prior to the flood, there had never been any rain. The flood also changed the geological stability of the earth. During the flood, the fountains of the deep were released. Vast underground stores of water were released upon the earth. Storms, floods, and earthquakes (in most cases) are simply the left over effects of Noah's flood.
The point is, there are three sources for events in our lives. God, Satan, and the decay of this world. Somethings are the direct result of God's hand in our lives. Somethings are the result of Satan's attacks against us. And somethings are simply the decaying away of this present world.
So, if God is sovereign, why does He allow evil things to happen to people? Why did God not bring a quick end to Job's suffering? Why doesn't God bring a quick end to evil in this world? The answer is complex and, in part, a great mystery. But Peter does tell us one reason, "Bear in mind that our Lord's patience means salvation" (2 Peter 3:15) God's patience in dealing with evil is so that more may be saved. God is not willing that any should be lost and He is willing to wait that as many as possible may be saved.
We must realize that God has many reasons for what He does and what He allows. While we may not understand all His reasons, we know he has a reason, and His reason is for our certain good.