The theology behind the Deuteronomic covenant is one of "just deserts." The good and faithful receive the blessings of God, while the wicked and unfaithful fall under the curses of God.
On the surface, this covenantal arrangement makes sense, God blesses the righteous and punishes the wicked. But upon deeper reflection there's some problems with this system, for both God and humans.
For God, the deep motivations of humanity are obscure under the Deuteronomic covenant. Are we obeying God freely and with love? Or are we obeying God for the rewards? The debate between God and Satan isn't a historical event, it's a dramatization of the question Heaven is asking of humanity.
For humanity's part, how can we trust God when good people suffer? Has not God, in those instances, broken the agreement? Per the Deuteronomic contract, is not God in the face of suffering to be considered untruthful, untrustworthy, and unreliable?
The point of all this is to say that Job isn't really about theodicy, about why good people suffer. The question at the heart of Job is if a relationship with God can transcend a punishment/reward system. The conclusion at the end of the book is that such a relationship is possible. It's hard, confusing, and painful, but it's possible. Job demonstrates before the Heavenly Court that our fidelity to God can transcend punishments and rewards. And God appears to give an account to humanity about what it's like running the cosmos. Good people may suffer, but God has not ceased sustaining, loving, and caring for the earth. There are aspects of God's covenantal fidelity to creation that we barely comprehend.
And thus, an understanding is reached between heaven and earth, a relationship emerges that moves beyond the Deuteronomic covenant.
