Katha-1-1-25-ye ye kāmā

Sri Shankara’s Commentary (Bhashya) translated by S. Sitarama Sastri

Ask, as you like, for all desired objects, which are covetable, but not easily attainable in the land of mortals. Again, here are these celestial nymphs (the term Râmâs meaning those who delight males) with their chariots and with their musical instruments; and women like these cannot be obtained by mortals without the grace of beings like us; with these female attendants given by me, have thy services performed, such as cleaning the feet with water, etc.; Oh Nachikêtas, it does not become you to put me the question connected with death, i.e., whether, when man is dead, there is or is not anything surviving—a question (as unprofitable as that) of examining the number of crow’s teeth.

Links
Various resources on the Kathopanishad
Upanishad Series – Katopanishad Commentary by Swami Chinmayananda