We have already seen that the texts teach the existence of the Absolute as ‘that from which all this comes forth’. But did they imply that this Being is actively involved in the creation and control of the world, or is it merely conceived as an actionless divine ground on which the world manifests through nescience?
Śaṅkara’s answer is that from the standpoint of the highest truth there is no plurality and no world and no Creator, and only the divine ground exists, if even the notions of existence or ground can be applied to it.
But from the standpoint of nescience the world of duality is a fact. And from that standpoint it is a grievous error to believe that the world-process goes on through the operation of any blind force and without the conscious support and control of an omniscient and omnipotent Lord.
To correct this error, the upanishadic texts speak occasionally of the Lord (īśa, etc.) and imply that He is the efficient and material cause of the universe, the Inner Ruler and Divine Magician who spreads forth the whole world-appearance under His own conscious control as a mere illusion.
~A J Alston from 'Shankara on the Creation', p.8