CHĀNDOGYA UPANISHAD · 1.1.10

तेनोभौ कुरुतः ।
यश् चैतद् एवं वेद यश् च न वेद ।
नाना तु विद्या चाविद्या च ।
यद् एव विद्यया करोति श्रद्धयोपनिषदा तद् एव वीर्यवत्तरं भवतीति खल्व् एतस्यैवाक्षरस्योपव्याख्यानं भवति ॥

tenobhau kurutaḥ ।
yaś caitad evaṃ veda yaś ca na veda ।
nānā tu vidyā cāvidyā ca ।
yad eva vidyayā karoti śraddhayopaniṣadā tad eva vīryavattaraṃ bhavatīti khalv etasyaivākṣarasyopavyākhyānaṃ bhavati ॥

Now therefore it would seem to follow, that both he who knows this (the true meaning of the syllable Om), and he who does not, perform the same sacrifice. But this is not so, for knowledge and ignorance are different. The sacrifice which a man performs with knowledge, faith, and the Upanishad is more powerful. This is the full account of the syllable Om.

F. Max Müller · The Upanishads, Sacred Books of the East 1 (1879)