Manifest from Non-Manifest

Know that before any emanations were emanated or any creations created, there was one simple [complete and perfect], supernal [exalted, transcendental] Light that filled all existence. There was no empty "place", no empty "space", or void. All reality was filled with that simple Or Ein Sof [Light Without End, or simply, Infinite Light]. There was no category of "beginning" and no category of "end". All was one, unified, simple, undifferentiated, ubiquitous and homogeneous, Infinite Light, called "Or Ein Sof".

When it arose in His simple [i.e. perfect] Will to create worlds and emanate emanations, to bring to light [i.e. express] the perfection of His actions, His Names and His Attributes – which was actually the purpose for creating all the universes…He constricted His Infinite Essence a a away from the center point of His Being, that is, from the very center of His Light [in order to create a "place" within which to emanate and create a system of differentiated dimensions or worlds]. [Of course, since Infinity has no center point, this is only said from the point of view of the "space" that is about to be created.] He thus constricted that Light, distancing it to the extremities around this center point, leaving a vacated space and hollow void...

Behold, after this constriction, which resulted in the creation of a "vacated space" and "hollow void" in the very midst of the Infinite Light of Ein Sof, there was a "place" for all that was to be emanated [Atzilut], created [Beriya], formed [Yetzira], and completed [Asiya]. He then drew forth a single, straight Ray from His Infinite Surrounding Light [and extended it down] into the vacated space. This Ray descended in stages into the vacated space. The upper extremity of this Ray touched and was drawn forth from the Infinite Light of Ein Sof [that surrounded the Space], and extended down [into the vacated space towards the center] but not all the way to the bottom extremity [so as not to cause the vacated space to collapse and merge back into G-d's Infinite Light]. It was through this Ray[serving as a conduit] that the Light of Ein Sof was drawn down and spread out below. Into this vacated space, He then emanated, created, formed and made/completed all the worlds. Through this Ray, which serves as a constricted conduit, the outpouring Supernal Light of Ein Sof spreads forth and flows down into the universes that are located within that Space and Void....

[From Etz Chaim in the Writings of the Ari, Shaar Rishon, Drush Igulim V'Yosher, Anaf Beit]