Yoga Sutras of Patanjali · 2.47

प्रयत्नशैथिल्यानन्तसमापत्तिभ्याम् ॥४७॥

prayatna-śaithilyānanta-samāpattibhyām

Asana is mastered by the relaxation of effort and by meditation on the infinite.

— Yoga Sutras of Patanjali 2.47

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).