The Imperium is a theocracy, and although the Arbites wield and police temporal authority, religious concepts make up the bedrock of Imperial Law. The Lex Imperialis holds that the Emperor rightfully expects service and obedience from every human being in the galaxy, and that within the Imperium that expectation is made manifest through the scripture of laws. To break the Lex Imperialis is not only to disobey a law of government, it is to violate the immaculate moral order those laws set out. This violation of a divine order is present in every crime the Arbites investigate, and once this is understood the need for harsh methods and stern penalties becomes clear. For the Arbites, there is no such thing as a petty crime.
From: Dark Heresy, Book of Judgement
