The 'Sri Vishnu Sahsasra Namavali' is a collection of one thousand names of Lord Vishnu. This collection of names appears in a part of the great epic Mahabharata, during a conversation between the great warriors 'Bhishma' and 'Yudhisthira.'
The names were handed down to Yudhisthira by Bhishma who was on his death-bed in the battlefield of Kurukshetra. Yudishthira sought the learned Bhishma's help opinion on the meaning of 'Dharma' or 'right action' and asked him the following questions :-
"What Dharma is the most superior among all the Dharmas in your opinion? By adorning whom does a living being get liberated from the unending cycle of birth and death?"
In a reply to this, Bhishma said, "Invoking and living in the presence of all-prevading Supreme Being Vishnu, and serving in Vishnu's names are the greatest forms of Dharma in my opinion." He then described Vishnu to Yudhisthira as the supreme light, the essence of the 'Universe', the all-pervading Brahman. All matter animate and inanimate, reside in him, and he turns in all matter. Bhishma then chanted the thousand names of Vishnu.
To this day, these names are considered to be powerful, potent mantras that invoke the blessings and energy of Lord Vishnu in our minds and hearts.
The first two names of Vishnu that Bhishma chanted, along with their English translations,
"OM VISHVASMAI NAMAHA"
Meaning:- Salutations to the ONE who is manifest as the entire Universe, who is omnipresent