Vishnu sahasranamam, slok104

Slok104:      Bhoorbhuvaha SwastarustAraha SavithA PrapitAmahaha
                     Yagno YagnapathiryajvA YagnAmgo YagnavAhanaha 

The self born Mighty Energised  Existence of earth and skys, the Sun, the Great grand father, the Sacrifice, the Lord of Sacrifice, the Result of Sacrifice, the part of Sacrifice and the Carrier of Sacrifice, is Sree Maha VISHNU. 

Here, in this slok the ancianity of Vishnu is explained by calling with a name,
"Great grand father". Many a times, it is mentioned in earlier slokas that Vishnu is a self born entity. Comparing Vishnu to Sun indicates the superabundency of Energies present in Vishnu.   

Here, Vishnu is addressed "Yagno". Yagna  is normally misinterpreted only as a Vedic ritual. But, the true interpretation is, "Sacrifice". Sacrifice means offering an oblation selflessly. Every selfless action is cosidered an act of sacrifice. Every sacrifice yields some result. ( Yagnaphal ).
Vishnu is the prompter, propellor, conducter and the result of any Sacrifice.
Every action runs with some charge and results with some amount of charge. This charged current hidden, can not be physically seen. That is Vishnu.  
If sacrifice is selfless, results are positive, and vice versa.
Every stage of sacrifice carries some amount of charge,  every action is charge bound.
Henceforth, which kind of Yagna one should opt is in one's own discretion.
Our Karmic currents are our life dectaters.Vishnu clears all bad karmic carrent, as Lord of Yagna, if we pray with total devotion.
. Vishnu's presence in any Yagna cannot be ruled out. In thri lokas, it is VISHNU who charges and discharges all actions.  

VISHNU  is the highly potential spiritual body, present everywhere  and  in
everything. The great grand father who takes the care of entire universe is
SREE MAHA VISHNU.  

              Om Vishnave namaha