Yoga Sutras of Patanjali · 1.33

मैत्रीकरुणामुदितोपेक्षाणां सुखदुःखपुण्यापुण्यविषयाणां भावनातश्चित्तप्रसादनम् ॥३३॥

maitrīkaruṇāmuditopekṣāṇāṁ sukhaduḥkhapuṇyāpuṇyaviṣayāṇāṁ bhāvanātaścittaprasādanam

The mind is clarified by cultivating friendliness towards the happy, compassion towards the suffering, joy towards the virtuous, and equanimity towards the non-virtuous.

— Yoga Sutras of Patanjali 1.33

Source: Sanskrit attributed to Patanjali (c. 2nd century BCE – 4th century CE). Public-domain English readings drawn from Swami Vivekananda's 'Raja Yoga' (1896) and Charles Johnston's 'The Yoga Sutras of Patanjali' (1912).