Sri Vishnu Sahasra Nama was revealed in the month of Magha, according to lunar calendar, on the 11th day of waxing moon, that is sukla paksha ekadasi which comes exactly after 2 months of Githopadesa.

Bheeshma Ekadasi is an auspicious occasion, the birth day of Sri Vishnu Sahasra Nama Sthothram. This sthothram was revealed to Pandavas by Bheeshmacharya when he was on the bed of arrows, after the Mahabharatha war. Lord Krishna revealed Bhagavad Githa to Arjuna. Though Arjuna was able to converse with Lord Krishna and clear many of his doubts, he couldn't absorb it completely as-it-is from the view point of the Lord. Fortunately, Sanjaya who is televiewing and explaining the happenings of the war to the blind King Dhrutharashtra was able to view this upadesam also through whom Bhagavad Githa came into this world. Ekadasi day(11th day of the full/new moon phase) is considered to be more holy day on which devotees take minimum food and spend most of their time contemplating on the Lord. It is the day on which the Saththvik nature in man blossoms more easily and opens up the way for one's enlightenment. How fortunate we are if we are with our Acharya taking upadesam from Him about the best of the secrets a man needs to know in his life !!

In the Kurukshethra war, between Pandavas and Kauravas, Krishna was the sarathi(charioteer) for Arjuna. After the day's battle, when they returned to the camp, Arjuna asked Krishna to get down and open the gate. This request baffled Krishna as He did not get the respect of a Guru who taught him Bhagavath Githa. Hence He concluded that, all His teaching was a waste. Then Krishna decided to choose an acharya who can teach dharma to Pandavas. According to the Githa’s Chapter 4 sloka 34,

Thath viddhi pranipathena pariprasnena sevaya
Upadekshyanthi the jnanam jnaninah thathva-darsinaha

The path of spiritual realization is difficult. Krishna therefore advises Pandavas to approach an enlightened master for the realization of dharma. The above sloka dictates the principle behavior of a student, to his teacher, before anything could be learnt from the master.

The student should surrender and this should be shown by a few activities which are dictated in the sloka. Prostrating before Guru, without any inhibition or ego Pranipatha. When the students are being taught, the disciple should be able to understand the essence of all those teachings. Thus, if the student gets a doubt, he should wait for the proper time and present them before his Guru in a prescribed way Pariprasnena. Gurus’ may not clarify the doubts at once, at times they wait few months or even years to test the disciples’ commitment and curiosity, and it may take a long time to get the answers. Till then the student should serve the master in a pleasing way which is called the "seva". Atlast the teacher who is a seer of the truth will reveal the ultimate secrets.

Krishna realizes that the most eligible person to talk about the ultimate truth would be Bheeshma, who at that time was lying on the bed of arrows in the battlefield, ready to leave his mortal body. Krishna took Pandavas to Bheeshma and requested pithamaha(grandsire) to teach the Pandavas about the Ultimate Truth and Dharma. Krishna promised pithamaha that He would restore his memory that was buried deep due to the pains in his body.

As it was imparted from a great acharya chosen by the Lord Himself, Sri Vishnu Sahasra Nama is considered the essence of Githa and all the Vedas.

Bheeshmacharya was lying on the bed of arrows after being put down by Arjuna during the war. After the war, Pandavas approached Bheeshma to teach them the higher principles of life and wisdom, from all his great experiences. Bheeshma who is a great Man of Action and Sacrifice, mastered the whole Dharma Sastra and practiced it strictly throughout his life. Even the Lord of Death feared to approach Bheeshma without his permission. Dharmaraja asks him to tell them the greatest of the secrets that made him so great and that he thinks is the best that can liberate all beings from the cycle of births and deaths and lead them to planes of highest Happiness, Bliss, The Lord. Then Bheeshmacharya having obtained boon from Lord Krishna to be able to speak in clear voice and memorise his past deeds reveals the essence of all that he learnt from a number of sages who had the vision of Lord in different forms. Bheeshma observed a number of austerities imposed by the sages, served them for long periods, satisfied them that he deserves to be taught the secret they have obtained after strenuous efforts, and finally obtained from them the secrets. Like a honey bee that collects the honey drops from all the flowers, Bheeshmacharya collected all the manthras from different sages and composed Sri Vishnu Sahasranama Sthothram which he used to practice daily. When Dharmaraja asked him to reveal the greatest of secrets, Bheeshma reveals this to Pandavas on Magha Suddha Ekadasi day in presence of Lord Krishna, showing Him and telling them that He is Lord of all Lords and praying Him with all 1000 names is all one can ever do to become more dear to Him which itself leads to salvation. Reciting it regularly or even listening to it is itself a great thing that empowers one with the strength to overcome all the difficulties and get on to the right path of Salvation.