The works of Ādi Śaṅkarācārya

Bṛhadāraṇyakopaniṣadbhāṣyam

Verse 247

अन्धं तमः प्रविशन्ति येऽविद्यामुपासते ।ततो भूय इव ते तमो य उ विद्यायाँ रताः ॥ १० ॥

In plain words

Those who worship ignorance walk into blind darkness. But those who lose themselves only in ritual knowledge walk into a darkness deeper still.

Close to the Sanskrit

Into blind darkness enter those who worship ignorance; into a darkness greater than that, as it were, enter those who delight in [mere ritual] knowledge.