You are the one who quoted the republic of plato! i thought you should know in what context he mentioned it.
He says that because Human Laws are made in consequence of natures laws but nature has no laws its only we who have responded to it. I dont know if you get it! In nature there is no Time, its eternal but laws change according to time. But nature doenst, i think the only other word you can use to explain it is Natures Characteristics.