Sri Vishnu Sahasra Nama is a collection of one thousand names of Lord Vishnu. It is recited both as a Stotra as well as a Namavali. The Vishnusahasranama as found in the Anushasana Parva of the Mahabharata is the most popular version of the 1,000 names of Vishnu. Other versions exists in the Padma Purana, Skanda Purana and Garuda Purana. Each name eulogizes one of His countless great attributes.
It appears in the Santi Parva of Mahabharata as a conversation between Grandsire Bhishma and Yudhistira. The context of the conversation is as follows: King Yudhistira approached grandsire Bhishma who was spending the final days of his stay on earth, with an intention to learn from him the secrets of Dharma for Bhishma was one of the 8 individuals considered to be the true knowers of Dharma.
After questioning and learning a number of other things, Yudhistira questions Bhishma thus: “What Dharma is the most superior among all Dharmas, in your opinion? By adoring whom does a living being get liberated from the samsara of birth and death?”
In reply to this Bhishma says, “Constantly worshipping and doing devotional service to Lord MahaVishnu is the greatest Dharma in my opinion”.
He then explains the omnipotence of the Lord and recites His one thousand names which is later on known as Vishnu Sahasranama / Vishnu Sahasranamavali or 1008 Names of Vishnu (Instead of 1000 Name it widely used as 1008 name of vishnu because 1008 is holy number)