It means the amount of energy is constant in isolated system. It also means that energy has no beginning nor an end. It existed before everything and the matters is the change form of energy….
Now can you believe that a substance (some might wanna call it God) existed before everything exist and the matters is formed as the change of the substance (some called it based on his image)
I’m sorry for my bad english but i think you can get the idea. Thanks 🙂