Vishnu sahasranamam, slok48

Slok48:    Yagna  Ijyo Mahejyascha  Krathuhu  Sathram  SathAm gathihi
                   SarvaDarcee  VimukthAtma  Sarvagno  GnAnamuttamam  

The  fruit of Sacrifice, the great force of action , the Ceremony, the place of 
Collection of celestial entities, the True Destination, the watcher of everything, the Atma of Liberation, the Knower of everything, the best  absolute Knowledge, is Sree Maha Vishnu.

Vishnu is the propellor of any action, and it's result. 

Vishnu  is the  witness of everything and every happening in this universe.

Vishnu is the Atma, containing everything in it, inside which any entity gets Liberation.
The Knower of everything,  the ultimate Knowledge is Sree Maha Vishnu. 
Nothing can escape Vishnu's  eyes. The  invisible"Eternal Witness"  is Vishnu.  

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Vishnu  is the  " Supreme Consciousness ". 

Vishnu is both, the oblation and the sacrifice.

Om Vishnave namaha