The God concept
Let's start by observing that most civilizations and individuals are developing a concept of God or Gods, even without outside preaching. Polytheistic religions Ancient Greeks and Romans had many Gods. Each God was powerful over a certain aspect of life. For example, Poseidon/Neptune governed the sea, storms, earthquakes. Each God embodied a certain aspect of live where human had little understanding about causation. Aphrodite/Venus governed the love, where humans still struggle to understand the causation.