Katha-1-3-9-vijñānasārathiryastu

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

What that goal is, is now explained; but the man who has discerning intelligence for the driver, whose mind is under control, and who is clean, i.e., the knowing man reaches the end of the road of Samsâra, i.e., realises the Supreme; i.e., is absolved from all the ties of Samsâra. The man of knowledge attains ¹ the highest place of Vishnu, i.e., the nature of the all-pervading Brahman, the Paramâtman known as Vâsudêva (the Self-luminous).

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