Katha-1-1-4-sa hovāca

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

Thinking that, as being the duty of a good son, he should ward off the undesirable consequences, which might befall his father on account of the imperfection in the sacrifice, by even giving himself away and thus perfect the sacrifice, he approached his father and said to him, ‘father, to whom, i.e., to which of the Ritviks will you give me as Dakshinâ, i.e., reward? though unheeded by his father thus addressed, he repeated the question a second time and a third time ‘to whom will you give me,’ ‘to whom will you give me?’ The father incensed at the thought that that was not like a boy said to the son ‘to Death do I give thee.’

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