Text:

अस्य विस्रंसमानस्य शरीरस्थस्य देहिनः ।
देहाद्विमुच्यमानस्य किमत्र परिशिष्यते । एतद्वैतत् ॥ ४ ॥

asya visraṃsamānasya śarīrasthasya dehinaḥ |
dehādvimucyamānasya kimatra pariśiṣyate | etadvaitat || 4 ||

4. When this atman seated in the body escapes from the body what here remains? This verily is that.

Shankara’s Commentary:

Again, of this atman in the body, visramsamanasya escaping. Dehinah embodied. The meaning of the word visramsamana is explained by the expression dehat vimuchyamanasya (being free from the body); what here remains? nothing of the whole lot of prana, etc., remains. Here in the body; the atman, on whose leaving the body, all this lot of effects and causes becomes in an instant enervated, destroyed and defunct, as in the case of the inhabitants of a city, when the lord of the city, is driven out of it, has been established to be some other than all this.