Yoga Sūtra Chapter Two verse 20
द्रष्टा दृशिमात्रः शुद्धोऽपि प्रत्ययानुपश्यः ॥२०॥
draṣṭā dṛśi-mātraḥ śuddhaḥ api-pratyaya-anupaśyaḥ ||20||
The seer alone sees, although pure it observes through psychic activity.
draṣṭṛ - seerdṛśi - seeingmātrā - only; measure, quantity, sum, size, durationśuddha - pureapi - alsopratyaya - psychic activityanupaśya - observes