VISHNU SAHASRANAMAM, SLOK35

Slok35:        Achyuthaha  PraDhithaha  PrANaha  PrANado  VAsavAnujaha
                      ApAmniDhi   raDhistana mapramattaha  prathistithaha

The Undepletable,  the birth propellant " Life force", the bestower of Life,  the brother to VAsava,  the treasure of Water,  and the ever alertfull,  established "SupremeCommander" is Sree Maha Vishnu. 

Vasudeva is the Godliness, present in every living being. That's  why, it is said that the Supreme Self is coexisting with the Embodied Self.  

Vishnu is the established ancient Chief Commander of the universe, since time 
unmeasurable.

What is undepletable?? The sum total of the Vital Energy, the " Jeeva " , which is the prime factor of the universal show never depletes. A little portion may transforms from one form to some other form.  Jeeva is the higher level disposition of Sreeman Vishnu.  The sum total quantity of Jeeva remains the same. That's why, it is said that Vishnu is Undepletable.

Om Vishnave namaha