“Friends can betray you but books are always loyal”
“Besides, there was no honor in betraying a loyal friend.”
“There is no friend as loyal as a book.”
“Friends can betray you, but with an old enemy, you always know where you stand.”
“There's ways you can trust an enemy you can't always trust a friend. An enemy's never going to betray your trust.”
“When you already believe something, how can you suddenly stop? When you are a loyal friend, how can you no longer be one?”