Religion is a primitive means of governance. Check out the Books of Laws in the Old Testament. This is literal civil code for the time lightly veiled as something mystical.

The problem is, the bigger a population becomes, the less wieldy religion becomes as a means of governance. It’s why cults work but the state of Iran (as one example) is rife with dissension and horrible enforcement laws. Too many people for stable governance via religion. Factions, insurgents, defectors will abound.