Bhagavad Gita · 11.8

न तु मां शक्यसे द्रष्टुमनेनैव स्वचक्षुषा।दिव्यं ददामि ते चक्षुः पश्य मे योगमैश्वरम्॥

na tu māṁ śhakyase draṣhṭum anenaiva sva-chakṣhuṣhā divyaṁ dadāmi te chakṣhuḥ paśhya me yogam aiśhvaram

But you cannot see me with your ordinary eyes. Therefore I give you divine eyes — behold my supreme yogic power!

— Bhagavad Gita 11.8

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)