The most powerful early humans were the cleverest humans, the ones who understood how to use this new capacity for language and abstract thought to their own advantage. They realized that by simply saying something is true in a sufficiently confident way, they could persuade the less clever humans to treat it as true.
Those clever humans used this newfound ability to place themselves in charge, and to make a bunch of rules to be passed down from generation to generation proclaiming that the less powerful humans must submit to the more powerful humans. Over the generations these rules became more and more numerous and complex, weaving in moralism, codes of filial piety, and insane, power-serving religions glorifying meekness, obedience and poverty.
But then, I believe in miracles.