These below two fantastic RigVedic hymns juxtapose and blend duality and non-duality brilliantly while summarising the essence of Veda and Vedanta!

गायन्ति त्वा गायत्रिणोऽर्चन्त्यर्कमर्किणः।

ब्रह्माणस्त्वा शतक्रत उद्वंशमिव येमिरे॥ १.०१०.०१

यत्सानोः सानुमारुहद्भूर्यस्पष्ट कर्त्वम्।

तदिन्द्रो अर्थं चेतति यूथेन वृष्णिरेजति॥ १.०१०.०२

Rig Veda 1.10.1-2 Rishi: Vishwamitra, Devata: Indra

Meaning: First verse establishes that there are multitudes of beings and hierarchies, though all are Self. Lord is arranged in a structure that contains Lords; Sun is worshipped, by Suns; and, Gayatri is sung of, by Gayatris!

Second verse speaks of how consciousness is aware of one level in this hierarchy and unaware of levels below

A simple example can drive the point home: When I open my eyes and some light falls on them, cells in the eye, cells in optical nerves and cells in brain work together to produce the notion that I am seeing so and so object. I am aware of the object, but not of various sensations in various cells

Vrish means to rain or storm. Vrishni is the deity who storms consciousness by stirring multitudes of its parts into action. But we are not aware of it. At the summit of those actions by those cells is Indra, who inspires an "understanding" (अर्थं चेतति) based on those multitudes of sensations. We are aware only of that understanding ("I am seeing so and so object") and not of all the sensations that brought it, just as one on a high summit does not see what is below clearly.

However, as the first verse says, Vrishni and multitudes of aspects of consciousness stirred into action by him, are all Self! The operational hierarchy does not imply superiority and inferiority. All are Self, but they do play different roles in a hierarchy. It is more nuanced than saying "all is Self and any division/duality is a delusion". Different aspect of Self play different roles in various hierarchical structures. When we are aware of one level in the hierarchy, the lower levels may be obscure or quite unclear. By extension, there may be higher summits supported by various realities/experiences we have now, on reaching which these realities/experiences may just fade away into obscurity!

~ Excerpt taken from chapter Dwaita vS Adwaitha in the book mārgabandhu written by Shri PVR Narasimha Rao Ji.