द्रष्टा दृशिमात्रः शुद्धोऽपि प्रत्ययानुपश्यः

drasta drsimatrah suddho’pi pratyayanupasyah

The seer is only the power of seeing and although pure, is seen through thoughts.

Yoga Sutras of Patanjali, 2.20

drasta = the seer
drsi = power of seeing
matrah = only
suddhah (suddho) = pure
api (‘pi) = although
pratyaya = thoughts
anupasyah = seeing