I'm sorry, but while what you're sayng is very interesting and probably factually true, it doesn't describe rule of law at all. Rule of law doesn't say anything about how new laws are created and by whom, but that the process by which this is dobe must be described in the body of law itself, implying that this process can only be altered by what the law describes and that all state activities must be backed by law.
Sure, the creation of the basis for this process is not itself an example of rule of law. But neither is the creation of law by a divine entity! The crucial part is thatrule of law doesn't say anything about how law is madw, but it requires the process to be defined in a specific place; the law itself.
Just to be clear: I'm not disputing about where this idea originated (although I'd say it was connectef to the Enlightenment, which was itself connected to the Reformation).
Firstly, my major purpose was to point out the existence of an independent judiciary and rule of law outside imaginary "Western Enlightenment". That's a cornerstone of the "rule of law".
Secondly, creation does matter a bit. If the edict of a ruler - his whim - is law, then it is effectively indistinguishable from despotism. Writing alone is not a check. If your written code of laws is nothing but a collection of a ruler's edicts - which is effectively what civil law is - there's nothing stopping the ruler from just changing it on the spot - i.e. making a new edict. The advantage of Sacred Law is that it places the creation of law outside the hand of rulers. You can't "change it on the spot" (or any spot for that matter).
Thirdly, and the most important point, is the interpretative function. This is really what gives the judiciary real power, and makes "rule of law" actually "rule of law". Interpreting the law gives judges a quasi-legislative function, and allows it to serve as a check on power.
This is something that Enlightenment thinkers didn't understand. Even the most acute of them - like Montesquieu - who did argue for independent judges, did not think they had interpretative power, and consequently overlooked them in discussing checks and balances. Enlightenment thinkers - like most people (save puritans) - thought judges were, and ought to be, merely "mouthpieces of the king". Or, in Revolutionary days, "mouthpieces of the People".
The idea of independent judges having interpretative power was, until the 19th C., ... weird. The judiciary is just part of the executive branch. What is a judge, after all? Isn't the king a judge? Isn't that his most fundamental function? It has been his duty from the earliest Medieval times to hold court, hear cases and pass judgment. Similarly for the aristocracy, in their dominions. The "king's judges", when he created them, were merely stand in for him, and speak for him. The judge passes judgement by the will of the king
(voluntas principis), and can only speak the words of the king. They have no power to interpret the law.
Again, this is something the Sacred Law tradition had. It made interpretation - deciphering meaning, distilling law, from the inchoate morass of scripture and traditions - became a central function of a judge. Rules of jurisprudence guiding interpretation were carefully delineated as a result. Religious judges, from the outset, had power of interpretation of the law, and so have a quasi-legislative function, which is
more power than rulers had.
If, say, the ruler wants to raise taxes, the judge can overrule him and say "no, you can't, it's against the law". If the king replies "well, I say I can", the judge can reply "Who cares what you say? You don't make the laws, God does". If the king insists and says "Well, I think I can. I don't think God's law forbids it", the judge can reply: "I interpret the law, not you; and I think God forbids it, so suck it."
So the king is in check, the law now constrains him. At several intermediate steps here ("I say I can", or, "I think I can") the king's judge in civil law would have to fall silent and conform.
Anyway, it is this interpretative power that is critical for "rule of law". This power of judicial review depends on the judges having power of interpretation. And this is not something Enlightenment thinkers understood. They thought that simply writing the law clearly was enough. It is not. Interpretive power was seized by the judiciary in the course of the 19th C., and philosophically blessed after the fact.
Religious judges had that power for eons. Indeed, in extremis, the Sacred Law can eliminate the king. Whereas the king's judges are the king's employees, not so religious judges. If the king decides to go ahead and raise taxes anyway, the judge can declare it unlawful and even depose the king ("This so-called King has broken God's law. It is lawful to disobey him. Heck, go ahead and remove him - he is not king anymore.") What 18th C. Enlightenment thinker thought unelected judges - the king's own judges, whose only authority comes from the king - had the right to license rebellion and depose Divinely-ordained monarchs? (well, a few murderous 17th C. Puritans & Jesuits did...but that's another story).
) but because "Ancient custom" says so.
