Religion plays a major role because each culture has their own teachings of a higher power that required each civilization to make offerings of blood, dance, prayers to their superior. example: The Astecs' usually required offerings of children, farm animals, ect, for rain to grow crops that they made breads out of along with other food staples.
It might be used later to limit rights that weren't originally listed. It was unnecessary because everyone had been granted basic freedoms. It was unnecessary because the new government had limited power.