If I owe a person money, and cannot pay him, and he threatens to put me in prison, another person can take the debt upon himself, and pay it for me. But if I have committed a crime, every circumstance of the case is changed. Moral justice cannot take the innocent for the guilty even if the innocent would offer itself. To suppose justice to do this, is to destroy the principle of its existence, which is the thing itself. It is then no longer justice. It is indiscriminate revenge.