Job is perfect. He has ten perfect children, a big, perfect ranch out in the countryside full of perfect camels, sheep, oxen and donkeys. He's perfectly pious, sacrificing for his own sins, plus a little bit extra in case one of his kids forgot. He's ripe for the taking, in other words.
So one day, some angels plus Satan are hanging out with god and they get to talking about Job. God brags that Job is his most righteous servant, a man who fears him and rejects evil. Satan's like, of course he loves you! You give him everything. If you took it all away, he'd curse you to your face. God: challenge accepted. The only rule is, Satan can't lay a hand on him.
One day, Job is alone when a servant approaches to say that he was plowing the fields when the Sabeans attacked and ran off with all the oxen and the donkeys. Then another servant appears and says god set fire to the sheep and some of the other field hands. Then a third servant appears and says the Chaldeans have run off with the camels and killed some more of the servants. Then a fourth servant appears to say a freak tornado came along and killed all seven of his sons, who were feasting at one of their houses. The girls apparently survived, but that's no comfort
Job rends his clothing, shaves his head, and starts to pray.