Yahweh is the self-existent one. The phrase "I AM WHO I AM" speaks to God's eternal, self-sufficient nature. God does not rely on anyone or anything for existence.

He has no beginning or end: Unlike created beings, Yahweh has always existed and will always exist.
He is the source of all life: All existence and purpose find their source and meaning in him. Without him, there is nothing.
He is utterly independent: God needs nothing to sustain, counsel, or support him. He is complete in himself