Bildad has progressed beyond calling Job to account for his unconfessed sins to charging Job with being evil and not knowing God.  Job admits that has gone astray but says that his error is his concern alone.  Job knows that God has allowed everything to happen.

Job relates that he not only has lost all his wealth, possessions, and children, he has lost his friends, prestige, and honor. While in the rock bottom of this pit, Job has an “epiphany moment”!

“I know that my Redeemer lives, and that in the end he will stand upon the earth. And after my skin has been destroyed, yet in my flesh I will see God; I myself will see him with my own eyes – I and not another. How my heart yearns within me!”

Earlier, Job questioned if there is life after death. His question is answered while he is in the depths of despair. Job knew!!! He knew about the Redeemer and he knew about everlasting life. He knew that that he would see God, and he would see God in his flesh. Ponder this...Job will be resurrected to rule in the millennium!

There is a great line in Job 21.
"Can anyone teach knowledge to God..." 
Sometimes we want to tell God what to do, like we know what's best for us.  HA!