The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 135

त एतदेव रूपमभिसंविशन्त्येतस्माद्रूपादुद्यन्ति ॥ २ ॥

In plain words

They merge completely into this very form, and rise out of it once more.

Close to the Sanskrit

They enter fully into this very form, and rise up from this form.