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एतच्छ्रुत्वा संपरिगृह्य मर्त्यः प्रवृह्य धर्म्यमणुमेतमाप्य ।
स मोदते मोदनीयँ हि लब्ध्वा विवृतँ सद्म नचिकेतसं मन्ये ॥ १३ ॥

etacchrutvā saṃparigṛhya martyaḥ pravṛhya dharmyamaṇumetamāpya ।
sa modate modanīyam̐ hi labdhvā vivṛtam̐ sadma naciketasaṃ manye ॥ 13 ॥

13. Having heard and well-grasped this, the mortal abstracting the virtuous atman, attaining this subtle atman, rejoices having obtained what causes joy. I think that the mansion is wide open for Nachiketas.

Shankara’s Commentary:

Again having heard this, the true atman which I shall explain to you—from the presence of the preceptor and well-grasped it as his own Self, having abstracted the virtuous atman from the body, etc., and having realized this subtle atman, the learned mortal rejoices having obtained what gives him joy, i.e., the atman. The door of such abode of Brahman is, I think, wide open for you, Nachiketas. The drift is ‘I think you worthy of emancipation.’