I love Charles Dickens' immortal novel, A Tale of Two Cities. I especially like the closing scene.
The setting is Paris during the French Revolution - an era of confusion and chaos. All the friends of King Louis XVI and Marie Antoinette were rounded up and executed by means of the guillotine.
Sydney Carton was a lawyer who had wasted his life. His client, Charles Darnay, was innocent, but since Carton failed to successfully defend him, Darnay was facing decapitation.
Sydney Carton went to the prison and exchanged clothes with Charles Darnay, thus setting him free.
The One I follow said, "Greater love has no one than this: that a person would lay down his life for a friend."