THERE is something so important in this Upanishad that, even in these short notes, it is necessary to dilate upon it to some extent.
It is concerning the secret that Yama was so reluctant to reveal to Nachiketas when he asked him the following question:
"This debate that there is over the man who has passed and some say 'This he is not' and some say that 'he is', that, taught by thee, I would know; this is the third boon of the boons of my choosing."
Why, we may ask, was Yama so reluctant to answer this question? The reply is that the secret related not to the objects of senses or of the speech or of the mind. It related to the complexity of the Self, the soul and the Supreme Being. And, as Yama explains at a certain stage of exposition:
"The Self is not to be won by eloquent teaching, nor by brain-power, nor by much learning: but only he whom this Being chooses can win Him; for to him this Self bares His body."