I like this too, but it raises the question for the first humans, where did that god idea come from?
The Decker quote handily answers that -- we create God in our own image. We wonder where the universe came from, and our first impulse is to draw an analogy with what we already know, which is where the things in our lives come from -- either they were born from a parent, like people and animals, or they were crafted by a person, like tools and buildings. A lot of older myths have the universe being born from an egg or from divine parents, but as technology advances, the myths become more about the universe being designed and fashioned by a creator. It's all just projecting ourselves onto the universe.
The cynical answer would be that God was made up by people who wanted to create organized religion as a way of having power over other people...
That comes later. It wouldn't work as a means of wielding power if it didn't already carry meaning for people. What organized religion does is to transform the idea of divinity from something that's about an individual's understanding of the universe and oneself into something that's about an authority demanding reverence and obedience from the masses.