The 1000 names of Vishnu.
Bhishma was defeated by Arjuna, he waited on a bed of arrows for the propitious time of death. Yudhishthira asked him for instruction. The dialogue is Vishnu Sahasranam in the 13th book of the Mahabharata.
Read Vishnu Sahasranam here
http://stotrarathna.blogspot.com/2018/04/vishnu-sahasranamam.html