Ekadasi

Fasting on the auspicious days of Ekadashi should be followed with certain prescribed rules in the scriptures.  The sacred scriptures describe the results of overlapped Ekadashi Vrutham or observance of the same without following the rules prescribed in the sacred texts.   It also illustrates the commendable rewards by observing Ekadashi with utmost faith and devotion.

Brahma Puranam says:

Purvam Thwaya Sabharyena Dasami Shesa Samyutha
Kruta Cha Ekadashi Rajan Tasya Idham Karanam Matham

Maithreya speaks to King Dhrutharashtra, as an answer to his question about why his 100 sons were killed at the Krukshetra war.   Maithreya narrates; King Dhrutharashtra had the pain of separation from his children for the reason that overlapped Ekadashi fast. 

Dasamey Ekadashim Purvam Samuposya Janardhana:
Abhyarchithas Thwaya Devi Thasyedha Karmana: Phalam

In the above verses Sage Valmiki describes to Devi Sita, the reason she had been impeled by Lord Rama from his Kingdom Ayodha to the woodland while she was pregnant with Lava and Kusha.

Gangodhakasya Sampurnam Yatha Thyajyam Ghatam Bhaveth
Suravindhu Samyuktham Tat Sarvam Madyatham Vrajeth

A cup of holy water of river Ganges which has been mixed with a drop of wine is not fit for consumption, just like the overlapped Eakadashi fast.

Garuda Puranam says:

Viddham Ekadashim Vipras Thyajanthey Yetham Manishina:
Thasyam Upositho Yathi Daridryam Dukham Yeva Cha

The end result of not following the Ekadashi Vrutham according to the prescribed rule results in Poverty and Misery.

Dwaparanthe Tu Gandhari Kuru Vansa Vivardhini
Karishyathi Cha Senani Mudha Bhavad Sikhi-Dhwaja
Thena Putra Satham Tasya Nasam Ishyathy Asamsayam

Dasamy Ekadashi Yatra Thatra Sannihitho Sura:
Dwadasy Ekadashi Yatra Thatra Sannihitho Hari:

In Dwapara Yuga, Gandhari who was the mother of 100 sons had to witness the death of her 100 sons and suffered the severe pain of separation.  The above verses describe the importance of observance of fast on Dashami and Ekadashi also the presence of Sura.  Further more describes the presence of Lord Sriman Narayana on Ekadashi and Dwadashi days.

Kurma Puranam says:Ekadasyam Uposyaiva Dwadasyam Paranam Smrtham
Trayodasyam Na Tat Kuryad Dwadasa Dwadasi-kshayath

One should observe complete fast on the Ekadashi day and break his/her fast  (Paranam) on Dwadashi day at the prescribed time, should not break fast on Tryodashi day or unprescribed time.

Skandhapuranam says:

Jagare Padmanabhasya Puranam Padathe Tu Ya:
Janma Koti Sukrutham Papam Dahathe Thularasi Vath

 Whoever worships Lord Hari – The Supreme Lord and recite Puranas and sacred scriptures would acquire the meritorious rewards, all their sins would burn into ashes like a cotton ball in the fire.