Mark Twain's quote

Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910), better known by his pen name Mark Twain, was an American author and humorist. He is most noted for his novels, The Adventures of Tom Sawyer (1876), and its sequel, Adventures of Huckleberry Finn (1885), the latter often called "the Great American Novel."

Be good and you will be lonesome. Following the Equator: A Journey Around the World
All right, then, I'll go to hell. The Adventures of Huckleberry Finn
Wheresoever she was, there was Eden. The Diary of Adam and Eve
Be respectful to your superiors, if you have any. The Wit and Wisdom of Mark Twain: A Book of Quotations
Write what you know. The Adventures of Tom Sawyer/Adventures of Huckleberry Finn