BṚHADĀRAṆYAKA UPANISHAD · 6.1.3

यो ह वै प्रतिष्ठां वेद प्रतितिष्ठति समे ।
प्रतितिष्ठति दुर्गे ।
चक्षुर् वै प्रतिष्ठा ।
चक्षुषा हि समे च दुर्गे च प्रतितिष्ठति ।
प्रतितिष्ठति समे प्रतितिष्ठति दुर्गे ।
य एवं वेद ॥

yo ha vai pratiṣṭhāṃ veda pratitiṣṭhati same ।
pratitiṣṭhati durge ।
cakṣur vai pratiṣṭhā ।
cakṣuṣā hi same ca durge ca pratitiṣṭhati ।
pratitiṣṭhati same pratitiṣṭhati durge ।
ya evaṃ veda ॥

He who knows the firm rest, becomes himself firm on even and uneven ground. The eye indeed is the firm rest, for by means of the eye a man stands firm on even and uneven ground. He who knows this, stands firm on even and uneven ground.

F. Max Müller · The Upanishads, Sacred Books of the East 15 (1884)