Ashadha maas ke Shukla paksha ki Ekadashi se Bhagwan Vishnu chaar maah ke liye Ksheersagar mein Shesh-shayya par yoga-nidra mein chale jaate hain — isiliye ise Devshayani (Hari-shayani / Padma) Ekadashi kehte hain. Yahin se Chaturmas aarambh hota hai, jiske chaar maah tak vivah, mundan, griha-pravesh jaise mangal kaarya rok diye jaate hain. Bhagwan Devutthana Ekadashi par hi phir se jaagte hain.
Katha ke anusaar Surya-vanshi pratapi raaja Mandhata ke rajya mein praja sukhi aur sampann thi. Par ek baar lagaataar teen varsh tak akaal (sukha) pad gaya — na megh barse, na anna uga, na yagya hue. Praja bhookh aur kasht se vyaakul ho uthhi aur raaja ke paas pukaar lekar aayi.
Vyathit raaja sena sahit van mein rishiyon ki khoj mein nikle aur Maharishi Angira ke aashram pahunche. Raaja ne haath jodkar akaal ka kaaran aur nivaaran poocha. Angira rishi ne kaha — "He raajan, tum praja sahit Ashadha Shukla Devshayani Ekadashi ka vidhi-poorvak vrat karo. Is vrat ke punya-prabhav se megh avashya barsenge."
Raaja Mandhata ne praja, mantri aur sena — sab ke saath shraddha se Devshayani Ekadashi ka vrat, upvaas aur Vishnu-pooja ki. Vrat sampann hote hi aakaash megho se ghir gaya aur jhamaajham varsha hui. Rajya phir se hara-bhara, dhan-dhaanya se sampann aur sukhi ho gaya.
Seekh: Devshayani Ekadashi sikhaati hai ki sankat ke samay samoohik shraddha, sanyam aur vrat se prakriti bhi prasann hoti hai aur sukh-samriddhi laut aati hai. Chaturmas sanyam, bhakti aur aatm-shuddhi ka kaal hai.