In Mark Twain’s Letters from Earth after a brief introduction by Twain, the story shifts to the letters written by Satan to his friends in heaven. In the first letter, Satan—who has been banished to Earth for one thousand “Earth days”— goes on to say that the people, the other animals, the earth itself are all insane. Nature itself is insane. This first letter is a very blunt statement on human arrogance and hypocrisy. He says goes on to explain his declaration over the course of the next ten letters.
The second letter explains the curiosity that is heaven as it is perceived on the earth. First and foremost, Satan points out that sexual intercourse is absent in this version of heaven. This is a peculiarity, due to the amount of emphasis placed on it during human life. He wonders why they would leave it out if they enjoy it so much on earth.
In fact, people have created a heaven full of things they don’t value. On earth, most men do not sing and/or cannot stand singing, very few people play instruments, people don’t like to pray, people are bored in church, everyone looks down upon everyone else, all “sane” people detest noise. Keeping that in mind, Satan wonders why then that “heaven” is full of endless church services where everyone loves everyone else while they all sing and play a musical instrument.
In letter three, Christianity is discussed. Satan claims that humans desire to be like (their) God, yet God is nobody to emulate. God punished Adam and Eve when he really had no reason to tempt them in the first place. He also continued to punish the next generations for a crime they did not commit (in regards to the forbidden fruit). People don’t treat their children that way, yet they claim to live in the image of God. He has set rules, yet he himself does not follow them.