It is an idea and is not exempt from the laws of nature, the laws of perpetual change. Nothing stays in a perpetual state of equilibrium, including our perception of ourselves, in spite of what religious institutions may desire. Things either eventually change through growth or things change through erosion. Religious institutions are no different. They cannot wish away the unnatural state of equilibrium just because they do not want to change.
Nobody likes change and religious institutions are no exception.
They can either accept change and grow or they will erode away as do all things in nature. Now for the concept of God. Religious institutions defy the laws of nature through professing that God is in a state of equilibrium. This is their Achilles heel, the point they guard jealously in order to avoid change. Their weak point lies in clinging to the concept that God is omniscient, omnipotent, and omnipresent.