But wouldn’t Job then have been justified in replying in outrage, “What! You mean you were using me to demonstrate something to Satan? You killed my wife and sons and cattle and tormented me merely because Satan wandered by?” …
… it was wrong of God to allow this, to treat Job’s life and that of his family, virtuous people, merely as educational material for Satan.
In the first place, God did not kill anyone, Satan did. Nor did God command Satan to harm Job; He merely allowed it.
Further, Satan argued: “Is it for nothing that Job is God-fearing? Have you not surrounded him and his family and all that he has with your protection?” (Job 1:9-10) This protection was God’s to give and God’s to take; Job did not have a right to be specially blessed by God. For God to withdraw this privilege according to his own counsel was not morally wrong.
Further, I could kidnap Nozick, put him in a hole on my land, and torment him, and God would (probably) not stop me. Satan is God’s creature who happens to hate humans, but Satan has as much freedom (for now before he is locked up in hell) to do as he pleases as I. If it pleases him to destroy humans, then God will not interfere into our war. Satan always had the power to afflict Job however he wanted; far from being guilty, God restrained Satan by saying “do not lay a hand on him.” Satan might never even have bothered with Job but singled him out for his trials because God mentioned Job first.
Nozick then advances some fantastic theories of why God asserted His glory in the end of the book (such as “God is in the middle of a hostile environment, sheltering us from outside forces, and bringing us along to the point where we can help him”).
But the essence of the story is not to murmur against the divine providence even in the face of great misfortunes. Whatever happens to you, remember that God is good.