Mbh 3.294.1a

“Markandeya said, ‘At length, O king, after a long time had passed away, the hour that had been appointed for the death of Satyavan arrived. And as the words that had been spoken by Narada were ever present in the mind of Savitri, she had counted the days as they passed. And having ascertained that her husband would die on the fourth day following, the damsel fasted day and night, observing the Triratra vow. And hearing of her vow, the king became exceedingly sorrow and rising up soothed Savitri and said these words, ‘This vow that thou hast begun to observe, O daughter of a king, is exceedingly hard; for it is extremely difficult to fast for three nights together!’ And hearing these words, Savitri said, ‘Thou needst not be sorry, O father! This vow I shall be able to observe! I have for certain undertaken this task with perseverance; and perseverance is the cause of the successful observance of vows.’ And having listened to her, Dyumatsena said, ‘I can by no means say unto thee, Do thou break thy vow. One like me should, on the contrary, say,--Do thou complete thy vow!’ And having said this to her, the high-minded Dyumatsena stopped. And Savitri continuing to fast began to look (lean) like a wooden doll. And, O bull of the Bharata race, thinking that her husband would die on the morrow, the woe-stricken Savitri, observing a fast, spent that night in extreme anguish. And when the Sun had risen about a couple of hand Savitri thinking within herself--To-day is that day, finished her morning rites, and offered oblations to the flaming fire. And bowing down unto the aged Brahmanas, and her father-in-law, and mother-in-law, she stood before them with joined hands, concentrating her senses. And for the welfare of Savitri, all the ascetics dwelling in that hermitage, uttered the auspicious benediction that she should never suffer widowhood. And Savitri immersed in contemplation accepted those words of the ascetics, mentally saying,--So be it!