Part 14 · Chapter 158

And it is therefore found that the light of the four sections of the Tefillin of the head returned and entered within the three inner Mochin, and their light protruded outward through the back, at the place of the nape; and that light became the aspect of the knot of the head Tefillin, in the shape of the letter Dalet, which is the secret of the Dalet of "Echad."