Hari Aum.
I will discuss here the final portion of the Katha Upanishad. Before this, I will very briefly summarise what we have covered so far.
The opening of the Upanishad begins with the young boy Nachiketas seeking knowledge.
Lord Yama, his Guru, first puts him to the test. Nachiketas' qualifications for seeking knowledge are examined-- does he have viveka (spiritual intelligence) and vairagya (disinterest in material objects as a result of true yearning for the spiritual Truth)? His statements suggest he does-- he turns down tempting offers of wealth and power, of pleasure, family, name and fame. He vows that he will accept nothing less than the Highest-- he declares he must have that and that alone. Thus, he demonstrates that he is a first class spiritual seeker. He has chosen the path of goodness (shreyas marga) over the path of pleasure/worldly delights (preyas marga).
Lord Yama then, pleased with his excellent and sincere disciple, teaches him the secrets of life and death, and about That which lies beyond.
The human body is described, a wondrous instrument, uniquely designed to allow the Spirit within to manifest Itself and be known to the human heart and mind. Various analogies are used to describe the union of Spirit and Matter that produce the human being-- the chariot yoked to restless horses, and the city of eleven gates.
The Self residing within the human heart, the goal of human life is described. It is Om, It is a mystery, imperceptible to the senses yet enlivening them all. Its nature is a splendour of a sort unimaginable. It is the Light of all lights, the highest and best of all that exists. It is to be known-- but not through those restless senses, but rather via the purified intellect and calm mind.
It is available to all, yet only known by the one who desires to know It most ardently, most earnestly and sincerely. It is so close, and yet so far. Although It is the heart of each one of us, the core of our very being, of our very existence, It is shrouded in mystery, hidden from us. We can attain It, but we must make ourselves deserving of It, we must persuade It to reveal Itself to us, to earn Its grace.
That Higher Self, that is everywhere, is visible only to the one who has developed the correct vision, the right perspective on life-- the ability to see unity in diversity, to recognise the Self that has manifested as the entire universe and as ourselves who reside within it.
So, having summarised what we have learned so far, let us now move forward and study the final portion of this Upanishad.
Lord Yama now says to Nachiketas:
The universe can be likened to a mystical tree which has its roots above and branches below (Sri Krishna also describes this tree to Arjuna in the Bhagavad Gita). The roots are Brahman, the origin, which is hidden and unmanifest. The visible branches that extend below is the universe of matter, of diverse names and forms. This is Brahman manifesting as matter, as ourselves. All the worlds exist within this mystical tree of life (the 'Ashwattha' tree in Sanskrit).
Brahman, though unseen, is the commander and upholder of this tree. The various forces of nature operate under His command. By His will and power, the fire burns, the wind blows, the sun shines, and creatures are born and die. He is the giver of Justice, He is the upholder of dharma (goodness/righteousness), and is therefore likened to a divine thunderbolt. (He does not permit unrighteousness to take hold in His Creation. He ensures that dharma ultimately always prevails). Due to fear of this Divine thunderbolt or His justice, the laws and forces of Creation/Nature (controlled by His divine energies, the devas) act in a precise and orderly manner.
Brahman is to be known by the human being before the body dies. (Note that this is not a state to be reached in the afterlife but rather, a state of consciousness to be reached while very much alive and within the human body). One who succeeds in attaining Him discovers one's true nature as immortal and experiences the bliss of this realisation. One who does not attain Him, however, will be reborn again in the world of matter (based on one's karma and then experience worldly joys and sorrows).
Lord Yama then states that higher than the senses is the mind. And higher than the mind, is the intellect. Higher than the intellect is cosmic intellect. Higher than the cosmic intellect is the Unmanifest. Higher yet than the Unmanifest is the Purusha (Brahman), the all-pervading One.
He says that Brahman cannot be seen by the eye (He is the origin of the eye, and transcends it). He can, however, be experienced by the higher spiritual mind, the spiritual heart.
When the senses, mind and intellect are calm and still (the state of meditation), then Brahman can be perceived.
He further says that the state of yoga, is the state of control of the senses. One must be watchful of the mind, as this state of yoga can come and go (therefore the spiritual seeker is advised to be cautious and self-aware).
When all worldly desires cease, then one attains Brahaman. This is the state in which all knots in the heart are cut asunder, and one becomes aware that one is immortal.
Lord Yama declares that there are one hundred and one channels of prana (energy) that travel from the heart space (within the astral/energy body) in various directions (these channels are called 'nadis' in Sanskrit).
Of these, one channel (the sushumna nadi) travels upwards from the heart space to the crown of the head (to the mystical 'eleventh gate' mentioned previously). The one who has attained immortality while living, departs the body by the eleventh gate at the time of death. Others, bound by various desires, leave via the other 'gates' and are reborn.
The Supreme Being, Purusha, resides in the heart of every being. One must strive to draw Him out just as one carefully dissects out the core of a plant from its outer layers (the stalk from a reed). He is pure and deathless, bright and immortal.
Nachiketas listened attentively to the entire teaching of Lord Yama. Having done so, he grasped their subtle essence and attained knowledge of his own true spiritual nature; he attained Brahman.
The Upanishad concludes with the declaration that, like Nachiketas, anyone who sincerely strives to know Brahman will succeed in their endeavour.
Please see below for a link to an article by Sivananda where he explains the essence of the Katha Upanishad:
By the grace of God, may we all become like Nachiketas, true spiritual seekers, and thus also attain knowledge of our own true, immortal nature as one with Brahman.
Om Namo Narayanaya.
Hari Aum Tat Sat.