This whole religion thing was copied from the Egyptians.
Much of the old testament is believed by believers to have been written around the time of Moses (1400s BCE).
But is easy to see where most of the nonsense originated. Here's an excerpt from the Wikopedia article entitled
"Ancient Egypt - Religious Beliefs".
Beliefs in the divine and in the afterlife were ingrained in ancient Egyptian civilization from its inception; pharaonic rule was based on the divine right of kings. The Egyptian pantheon was populated by gods who had supernatural powers and were called on for help or protection. However, the gods were not always viewed as benevolent, and Egyptians believed they had to be appeased with offerings and prayers. The structure of this pantheon changed continually as new deities were promoted in the hierarchy, but priests made no effort to organize the diverse and sometimes conflicting creation myths and stories into a coherent system. These various conceptions of divinity were not considered contradictory but rather layers in the multiple facets of reality.
After the New Kingdom, the pharaoh's role as a spiritual intermediary was de-emphasized as religious customs shifted to direct worship of the gods. As a result, priests developed a system of oracles (read that as "prophets" in your world) to communicate the will of the gods directly to the people.
The Egyptians believed that every human being was composed of physical and spiritual parts or aspects. In addition to the body, each person had a šwt (shadow), a ba (personality or soul), a ka (life-force), and a name. The heart, rather than the brain, was considered the seat of thoughts and emotions. After death, the spiritual aspects were released from the body and could move at will, but they required the physical remains (or a substitute, such as a statue) as a permanent home. The ultimate goal of the deceased was to rejoin his ka and ba and become one of the "blessed dead", living on as an akh, or "effective one". In order for this to happen, the deceased had to be judged worthy in a trial, in which the heart was weighed against a "feather of truth". If deemed worthy, the deceased could continue their existence on earth in spiritual form
WOW - guess where the idea of heaven came from? the idea of the soul?