Srimad Bhagavatam Canto 10, Chapter 85, Text 05

SB 10.85.5

etan nana-vidham visvam
 atma-srstam adhoksaja
atmananupravisyatman
 prano jivo bibharsy aja
 
Translation: 
 
O transcendental Lord, from Yourself You created this entire variegated universe, and then You entered within it in Your personal form as the Supersoul. In this way, O unborn Supreme Soul, as the life force and consciousness of everyone, You maintain the creation.
 
Purport: 
 
When creating the material universe, the Lord expands Himself as the Paramatma, or Supersoul, and accepts the creation as His universal body. No material body has any reason for existing without some jiva soul desiring it for his enjoyment, and no jiva can independently maintain a body without the Paramatma accompanying him there for guidance. The Vaisnava acaryas, in their commentaries on the Second Canto of Srimad Bhagavatam, explain that even before Brahma is born from the lotus navel of Garbhodakasayi Visnu, he first accepts the whole material energy, the mahat-tattva, as his body. Thus Brahma is the jiva embodied by the universe, and Visnu is the Paramatma who joins him. Brahma must organize the specific manifestations of creation, but he cannot begin to do so until Lord Visnu expands Himself again into the subtle energy of action — which is the sutra-tattva, or original vital air — and also into the creative energy of consciousness, buddhi-tattva.
Srimad Bhagavatam Canto 10, Chapter 85, Text 04
Srimad Bhagavatam Canto 10, Chapter 85, Text 06