Padma purana embodies an episode that illustrates the greatness of this day.
The story goes that once Mura, the son of Talajangha became a terror to the pious and caused grief in several
ways. Even the august Trio were not spared. At times they used to take to heels to places of safety.
It happened to Sri Maha Vishnu too. Harassed by his asura krityas, Vishnu went to Badarikasram for
temporary relief. He selected Simhavathi Cave for rest. Before entering it, he gave word to his
yogamaya to keep guard the Cave.
Mura searching for him reached this
spot. Seeing Mura approaching in his terrific expect, yogamaya created one goddess called
Ekadasi Devi as powerful as, nay more powerful than Mura. In the encounter, the
dreadful demon was destroyed. Vishnu learnt on waking up all that happened during the
period of his rest. Gratified with her powers and devotion, he blessed her with a boon the ability to destroy
the sins of people, who observe fast and offer prayers on that day called Ekadasi Day.
Since then the adorers of Vishnu observe fast on this day and offer soulful prayers.