Katha-1-2-17-etadālambanam̐

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

Com.—This being so, this prop is the best, i.e., the most praiseworthy of all props, to attain the Brahman. This prop is both the higher and lower; for, it leads to both the highest and the manifested Brahman i.e., of the highest Brahman and the manifested Brahman. The meaning is: he becomes one with the Brahman and he becomes fit to be worshipped like Brahman.

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