Mahabharata — Anushasana Parva, Shloka 1366
मानसतीर्थ-शौचप्रशंसा | Praise of the ‘Mental Tīrtha’ and the Marks of Purity
महर्षित्वमथासाद्य सशरीरगतिर्भवेत् । दस वर्षोतक एक-एक मास उपवास करके एकतीसवें दिन भोजन करनेवाला पुरुष उत्तम स्वर्ग लोकको जाता है। वह महर्षि पदको प्राप्त होकर सशरीर दिव्यलोककी यात्रा करता है
maharṣitvam athāsādya saśarīragatir bhavet | daśa varṣotaka eka-eka māsa upavāsa kṛtvā ekatriṃśe dine bhojanaṃ kurvan puruṣa uttamaṃ svargalokaṃ gacchati | sa maharṣipadaṃ prāpya saśarīraṃ divyalokaṃ yātrāṃ karoti |
毗湿摩说道：得大圣仙（摩诃利希）之位者，甚至能以此身继续前行。若有人十年之久，每月持斋禁食，只在第三十一日进食，便能到达至高天界。既获大圣仙之品阶，他以化成神妙之身，行旅于神圣之域。
भीष्म उवाच
Educational Q&A
Sustained austerity—specifically long-term, disciplined fasting with strict regulation of eating—is presented as a powerful dharmic practice that yields extraordinary spiritual merit, culminating in attainment of the highest heaven and even a ‘bodily’ passage to a divine realm.
In Bhishma’s instruction on dharma, he describes the फल (result) of a particular vrata: a person who fasts each month and eats only on the thirty-first day, continuing this for ten years, gains the status of a great rishi and reaches Svarga/Divyaloka, portrayed as an exalted post-mortem (or transfigured) destination.