AITAREYA UPANISHAD · 1.3.5

तच्चक्षुषाजिघृक्षत् तन्नाशक्नोच्चक्षुषा ग्रहीतुं स यद्धैनच्चक्षुषाग्रहैष्यद् दृष्ट्वा हैवान्नमत्रप्स्यत् ॥ ५ ॥

taccakṣuṣājighṛkṣat tannāśaknoccakṣuṣā grahītuṃ sa yaddhainaccakṣuṣāgrahaiṣyad dṛṣṭvā haivānnamatrapsyat ॥ 5 ॥

By the eye He would have seized it, but He could not seize it by the eye. Had He seized it by the eye, then would a man be satisfied by merely seeing food.