Yoga Sutras of Patanjali · 2.21

तदर्थ एव दृश्यस्यात्मा ॥२१॥

tad-artha eva dṛśyasyātmā

The very nature of the seen is to exist for the seer.

— Yoga Sutras of Patanjali 2.21

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).