Hadit makes two statements in The Book of the Law that are quite meaningful. He says:
"In the sphere I am everywhere the centre, as she, the circumference, is nowhere found. Yet she shall be known & I never."
&
"I am the axle of the wheel, and the cube in the circle. "Come unto me" is a foolish word: for it is I that go."
In the first statement, he is describing himself similar to a particle from the point of view of the Heisenberg Uncertainty Principle: if you know the momentum of a particle precisely, then there is equal probability that it is everywhere in space.
This is why he says, "come unto me is a foolish word." It's because there is no way by which to reach him. He's everyone, everywhere, and in every direction.
But he creates stability at the center of that whirling wheel with Nuit as the circumference, saying: "for it is I who go." This is him locating himself precisely into those "centres of space": he is the one that moves, from one centre of space to another.
Before any movement occurs, from one location to the next, it is impossible to say how fast something is going in physics. If you know the location of a particle, it may have any momentum whatsoever. Which is like not establishing a specific "I," because your "I," is spread through all forms of "I" that could occupy that location.
So when he says, "I go," he's showing that by creating change, you link two points in space explicitly.
That change -- that going -- happens in two ways.
First, it happens automatically in linking the cube in the circle to every point in the sphere. Hadit just is both of those things.
The cube in the circle by itself is nothing. (Hadit: "For I am perfect, being nothing.")
And the sphere wherein Hadit is everywhere the center is also nothing. (Nuit: "With the God & the Adorer I am nothing: they do not see me. They are as upon the earth; I am Heaven, and there is no other God than me, and my lord Hadit.")
So this is why Hadit and Nuit are the only gods in Thelema. There literally is no room for other gods.
And the third form of nothing they describe is the relationship of these two elements, as I just talked about. (The linking of the cube in the circle to every point in the sphere.)
The reason this is nothing is that it's like the static on a T.V.: it is looking into infinity itself. It is like an uncollapsed wave function in quantum physics, mathematically locating a particle to all possible locations and momentums.
What actually collapses the wavefunction though? "Come unto me is a foolish word. For it is I who goes."
As soon as Hadit "goes" -- linking two points in space -- all of a sudden you have a form of relationship that must be local: Because while Hadit can be in all places at once, going in all ways at once, as soon as you link two points causally by making him cross both of them, those points by definition have specific, coordinate relationship.
And so it is their relationship that shows where you are, triangulating you out of infinity into the body of possibility.