Upanisads of Sri Shukla Yajur
"Upa-ni-sad" means to "sit near by". The Upanisads are the teachings imparted by a guru to his student sitting at his feet. It could also mean "that which takes one to Brahman". The Upanisads occur at the end of Aranyaka. If Samhita is the tree, the Brahmanas are the fruits and Upanisads are ripened fruits, the ultimate benefits of the Vedas. After spending the life according to the Samhita and Brahmana rituals one gets mature enough to go to the next higher level of realising Brahman in which state he achieves the ultimate bliss and there is no birth after realising Brahman. Even though there are mention about deities and mantras the ultimate goal is self realisation. Upanisads, Brahma Sutra and Bhagavad Gita are grouped under the name "Prasthana Thrayav and considered as the ultimate touchstone of the truths. The renowned philosophers world over feel" Upanisads are the crowning jewels of intellectual exercise and they represent the highest peak of thought process" men could possibly hope to attain.
In other philosophies the inquiry is at the intellectual level whereas in our Indian philosophy the quest is inwards and one has to experience rather than having simple knowledge. In order to achieve this highest level one has to dissolve his self in the Brahman and to achieve this he becomes a sanyasin after getting mature doing the rituals mentioned in Samhitas and Brahmanas. When a person is initiated into sanyasa he is taught the four mantras called Mahavakyas which occur in Upanisads. By constantly and vigorously meditating on these mantras the Sanyasi achieves the self realisation. It is also clearly stated and believed that a mere study of the Upanisads with the knowledge of Sanskrit or with the help of books cannot lead to the self realisation. A person has to involve deeply in true sadhana of self purification and meditation. He has to repeatedly study and meditate on the meaning of the mantras and slokas under the expert guidance of a learned Guru. Such a rigorous and austere life can only lead him to realisation of Atman and attainment of true bliss.
In Shukla Yajur Veda a number of Upanisads are found and the most important are Isavasya Upanisad and Brahadaranya Upanisad, the latter is by far the biggest of all the Upanisads known. The other Upanisads are: Yagnavalkya Upanisad, Jabalopanisad and Paramahamsopanisad, Mandalbrahmanopanisad, Thrisikibrahmanopanisad, Niralambonisad, Manthrikopanisad, Sulabhonisad etc.
Brhadaranya Upanisad is byfar the greatest and biggest of the Upanisads, biggest because it contains three Kandas and Adhyayas containing about slokas, greatest because it expounds the concept of Brhat or Brahman identical with Atman as all embracing, illimitable, absolute, self luminous and blissful reality. The Sankara bashya by Adi Sankara is acclaimed as the greatest interpretation of this Upanisad. Adi Sankara explains in his bashya how the great truth of Brahman-Atman identity forms the basis of all the Vedantic Texts in general and in this great Upanisad in particular.
Discussion between Raigravarishi and Gora Angirasa about how the universe was formed and has 16 kandas.
Consists of 16 slokas and defines Brahman.
Consists of 20 slokas and defines the characteristics of a Sanyasi
This is a discussion between Thrisikibrahmana who reached Surya loka and inquired him about body, prana and atman and has 164 slokas.
A discussion between Sri Yogeeswara Yagnavalkya and Surya Bhagavan and has 5 Brahmanas.
Sri Narada asked Sri Bhagavan "Which are the paths of the yogis called Paramahamsas and what is their aim?"
Sri Bhagavan replied "The path of a Paramahamsa is extremely difficult to achieve. Paramahamsas are not many, one can be seen very rarely. He is totally divine. The learned know that a Paramahamsa is Veda Purusha himself. He is a great soul. His mind is always dwells on me. I also dwell in him always. He, leaving his wife, children and relatives, removing hair, yagnopaveetham (poonal), not indulging in any karmas including Veda adhyayanam, forsaking this big world itself, for the sake of decency and for the sake of convenience he has a langod wrapping a towel around it and also a dandam. Even this is not important to him.
He travels everywhere without even a dandam or hair or poonal without minding heat or cold. He does not have passions or distress. He is not bothered about mana or apamana (self respect or abuse). Without anger, pride, astonishment or wants or avarice or ostentation he considers his body as a dead body. He, having totally detaching himself from the body which was the cause of doubts and avidya, having realised the supreme truth of his Atman sees himself as Supreme Bliss and Supreme truth. He has attained the supreme truth that Atman and Paramatman are one and the same. This merger (sandi) is his Sandya Upasana.
Whoever is able to totally destroy all desires and dwells always in the state of Advaita he possess the danda of Gnana and he is called Ekadandi.