What is the core idea of monotheism?

The core idea of monotheism is the belief in a single, all-powerful God. This is in contrast to polytheism, which believes in multiple gods, and atheism, which denies the existence of any god. Monotheism asserts that there is only one God who is the creator and ruler of the universe. This God is often described as being omnipotent (all-powerful), omniscient (all-knowing), and omnibenevolent (all-good). Examples of monotheistic religions include Christianity, Islam, and Judaism.