लोकादिमग्निं तमुवाच तस्मै या इष्टका यावतीर्वा यथा वा । स चापि तत्प्रत्यवदद्यथोक्तं अथास्य मृत्युः पुनरेवाह तुष्टः ॥ १५॥

ॐ

English Translation

Yama then told him about the Fire, which is the source of the worlds and what bricks were to be gathered for the altar and how many and how the sacrificial fire was to be lighted. Nachiketa, too, repeated all this as it had been told him. Then Yama, being pleased with him, spoke again. 

ॐ

Commentary

This, the Sruti itself says. Death explained o Nachikêtas, the fire, which was the source of the worlds, being the first embodied existence, the same that was asked for by Nachikêtas; again he told him of what form the sacrificial bricks were to be, how many in number and in what manner the sacrificial fire was to be lit and all this; Nachikêtas also faithfully repeated what was told him by Death. Then delighted by his repetition, Death said to him again inclined to grant him a boon other than the three promised.

Sri Shankaracharya