The works of Ādi Śaṅkarācārya

Bṛhadāraṇyakopaniṣadbhāṣyam

Verse 254

एकधैवानुद्रष्टव्यमेतदप्रमयं ध्रुवम् ।विरजः पर आकाशादज आत्मा महान्ध्रुवः ॥ २० ॥

In plain words

There is only one way to see this: it cannot be measured, it never shifts, it carries no stain, it is beyond even space, unborn, the self, vast, eternal.

Close to the Sanskrit

In a single way alone is this to be perceived: unmeasurable, constant, free from taint, beyond space, unborn, the self, great, eternal.