The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Verse 131

त एतदेव रूपमभिसंविशन्त्येतस्माद्रू-पादुपद्यन्ति ॥ २ ॥

In plain words

They merge completely into this very form, and from this very form they emerge.

Close to the Sanskrit

They enter completely into this very form, and they arise from this very form.