Śvetadvīpa-varṇana and Śāstra-pravartana (Śānti Parva 322)
मलिनं हि यथा वस्त्र पश्चाच्छुद्धयति वारिणा | उपवासै: प्रतप्तानां दीर्घ सुखमनन्तकम्
Bhishma said: As a soiled garment is later cleansed by water, so those who are tempered by austerity through fasting—when their inner being is purified—attain great happiness, long-lasting and without end.
भीष्म उवाच