Yoga Sutras of Patanjali · 2.20

द्रष्टा दृशिमात्रः शुद्धोऽपि प्रत्ययानुपश्यः ॥२०॥

draṣṭā dṛśimātraḥ śuddho'pi pratyayānupaśyaḥ

The seer is mere seeing — pure consciousness — and though pure, it appears to see through the modifications of the mind.

— Yoga Sutras of Patanjali 2.20

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).