This is ultimately rooted in the infinite light ("Ohr Ein Sof") that preceded Creation, the Tzimtzum and the Sephirot, rather than the source of the immanent light in the "Kav" (first emanation of creation after the Tzimtzum), in the teachings of Isaac Luria.
This is fundamentally based on the boundless light ("Eternal Light") that existed prior to Creation, the Tzimtzum, and the Sephirot, as opposed to the source of the immanent light in the "Kav" (the first emanation following the Tzimtzum), according to Isaac Luria's teachings.