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 rooted in the infinite radiance ("Eternal Light") that preceded Creation, the contraction (Tzimtzum), and the Sephirotic emanations, rather than the source of the inherent light in the "Kav" (the first creative emanation following the Tzimtzum), as taught by Isaac Luria.