One of the dominant themes in Boehme’s writings is the utter transcendence of God: His existence outside time and space, inaccessible to all human thought, ineffable by any human tongue.
What then is left which we can conceive of? Nothing is left, a nothing which Boehme calls the Ungrund, often translated into English by the word Abyss, a depth which has no end, a bottomless empty nothingness. …
This Ungrund can only be imagined and is the primal image of the unknowable entity who in traditional wisdom is not to be given a name but can only be announced as ‘I AM’.
Jacob Boehme (Western Esoteric Masters Series), edited and introduced by Robin Waterfield, North Atlantic Books, Berkeley, CA, 2001. pp. 26-27.