The main idea of the passage above from Cotton Mather's "The Wonders of the Invisible World" is to justify the outcome of the trials. Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.
He starts having to struggle with fear, discomfort, and isolation. This marks a shift for a man used to having an always pleasant life. Still, he's hopeful at first that the doctors can get rid of whatever condition it is that's bothering him and restore life to normal. Ivan becomes isolated from he world around him. All that seemed to matter before stops mattering. Ivan's death forces him to painfully re-evaluate his own life, illustrating Tolstoy's belief that only death can reveal life's meaning. When he says "Death is finished," he is referring to the spiritual death that has characterized his whole life. It's the final moment of realization, and the one that brings everything to a conclusion. Ivan sees that his life was wrong. He actually tries to figure out why he wants to live, and realizes the very life he's been wanting to go back to all this time has been not so great. Perhaps he hasn't lived his life as he should. After, he feels compassion for his family, and recognizes that by dying he can at last do them a service. Now he's ready to die, and even happy to do it. No more tension.
He wants to change the misconception that most slaves sing their lungs out because they feel happy.
