Job is a very wealthy, righteous man. The devil believes the only reason Job is righteous is because of his riches, and asks God to allow him to try Job. As a result, every imaginable trial comes to Job: he loses his riches and family, receives painful boils all over his body, and his friends encourage him to curse God and die.
Job refuses to follow his friend's advice, and even though he can't understand why he is suffering such severe trials, continues to say "I know that my Redeemer Liveth." After all the trials, Job is blessed by God, and receives a new family, more wealth, and relief to the boils.