The principle of Righteousness is an integral part of the Cretan and Spartan republics. (Wheeler, "The Spartan Republic"). This is also the major theme of Plato's Republic. Plato’s Republic is based on the Doric Greek societies and their philosophy, especially the application dikaios (Morgenstern, cited in Müller, 1839: II, 193)

Now, in the Republic IV §433, (Jowett paperback, pg 149), Socrates says:

"Then on this view also Justice will be admitted to be the having and doing what is a man's own, and belongs to him?
"...But when the cobbler or any other man whom nature designed to be a trader, having his heart lifted up by wealth or strength or the number of his followers, or any like advantage, attempts to force his way into the class of warriors, or a warrior into that of legislaors and guardians, for which he is unfitted, and either to take the implements or the duties of the other; or when one man is trader, legislator and warrior all in one, then I think you will agree with in saying that this interchange and this meddling of one with another is the ruin of the state.
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(((Notice the trifunctionality here)))) "Seeing then, I said, that there are THREE distinct classes, any meddling of one with another, or the change of one into another , is the greater harm to the state, and may be most justly termed evil-doing".
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"This then is injustice: and on the other hand when the trader, the auxiliary, and the guardian EACH DO THEIR OWN BUSINESS, that is JUSTICE, and will make the city just".

This "Each do their own business" is a principle of the Natural Law. It is observed in the Natural Order. That all things stay in their place. Accept their boundaries/limits. This is Dike. All things in the cosmos has Dike.---So when the Doric Greeks made their governments---they copied this principle into their State. Following Dike, "The dictates of righteousness would state that each class was given one duty that its nature suited it for to perform. To Royalty was given the office of executive, to the Aristocracy (its old function) of counsel and to the soldiers a voice of consent or dissent. " (Wheeler, W. Lindsay, The Spartan Republic, SPARTA journal, http://www.sparta.markoulakispublications.org.uk/index.php?id=105

Now, Jowett uses the word "justice" but I chose the word "Righteousness". In an earlier post, Dikaiosyne/Righteousness is a Virtue. Here, dikaios is a Principle of the Natural Law. Is "obedience" a concomitmant of Righteousness? Does Justice in the Greek mentality means to remain at one's station in life?

Many people ascribe this saying to Aristotle, "To treat unequal things equally is injustice". But it is found in Plato's Laws §757, "There can never be friendship between the slave and his owner, nor between base and the noble when equal honors are bestowed on both; indeed, equal treatment of the unequal ends in Inequality when not qualified by due proportion."

Dike would then include "due proportion". Otherwise it would be "adikia".