It is said that on the day of Vaikuntha Ekadasi, the doors of Vaikuntha (Vishnu’s abode) is thrown open. In other words heaven is open for the common man. There are many stories associated with Vaikuntha Ekadasi. In general, Ekadasi in any month, is considered as a time for contemplation, prayers and fasting. What is the reason behind this tradition of observing fast and quietude on this particular day?
Of course its hard to pin point one reason behind this age old tradition. However, one may notice that an Ekadasi day is always partly ruled by ‘Vishti’ Karana. A Karana is one of the five components of the Hindu Panchanga and is taken as half of a ‘Thithi’ (in simpler terms, one half of a day).
Vishti Karana is ruled by Yama (& the planet Saturn) and is considered poisonous and malefic in terms of any deeds undertaken on this day. Since every Ekadasi has Vishti Karana, doesn’t it make sense that you fast on this day. You also digress into prayers to avoid doing any major tasks this day. This is just a thought and possibly one among a plethora of reasons behind the traditions of Ekadasi.