Tvameva kevalam Dhartaasi:

You are verily the unswering upholder.-He is the Righteousness and upholds and sustains it. He is from whom all the beings are born, live and also depart back to him. Between the birth and depart they seek to know Brahman. He is the cause of the world as Substratum ( Adhoshtana) He is the material cause as well instrumental cause of the world.

Chapter 7: bHAGAVADGEETE Knowledge of the Absolute

SLOKA 6

etad-yonini bhutani
sarvanity upadharaya
aham krtsnasya jagatah
prabhavah pralayas tatha

6. Know that all beings have their birth in these. So, I  am the source and dissolution of the whole universe. These, My inferior Nature (Prakriti) and My superior Nature (PrakritiJ matter (Kshetra) and spirit (Kshetrajna) are the womb of all creatures. Because my Prakriti is the’

womb of all beings, I am the origin aud the end of the whole universe. That is to say, through this twofold Prakriti, I, the omniscient Isvara, am the cause of the universe.

TRANSLATION

Of all that is material and all that is spiritual in this world, know for certain that I am both its origin and dissolution.

PURPORT

Everything that exists is a product of matter and spirit. Spirit is the basic field of creation, and matter is created by spirit ( Chetana) . Spirit is not created at a certain stage of material development. Rather, this material world is manifested only on the basis of spiritual energy. This material body is developed because spirit is present within matter; a child grows gradually to boyhood and then to manhood because of that superior energy, spirit soul, being present. Similarly, the entire cosmic manifestation of the gigantic universe is developed because of the presence of the Super soul, Visnu. Therefore spirit and matter, which combine together to manifest this gigantic universal form, are originally two energies of the Lord, and consequently the Lord is the original cause of everything. A fragmental part and parcel of the Lord, namely, the living entity, may by manipulation of material energy construct a skyscraper, factory or city, but he cannot create matter out of nothing, and he certainly cannot construct a planet or a universe. The cause of the universe is the Supersoul, Krsna, the supreme creator of all individual souls and the original cause of all c auses,

Katha Upanisad confirms: nityo nityanam cetanas cetananam.