This is the thirteenth Upanisad in the list of Upanisads called Mukthikopanisads as it deals with the ways to reach Mukthi. This begins with the Santhipad of Sri Shukla Yajur Veda "Om Purnamadha".etc. This was composed by Jabala Rsi and hence is called Jabalopanisad.
This consists of six kandas. The first kanda called Avimuktham and deals with "kurushetram" which is the centre of the forehead. If a person, who knows this as brahmasthanam, is given the upadesa by Sri Rudrar to attain Mukthi.
The second kanda says the centre of the forehead is Varanasi, the third kanda deals with the importance of Rudra Japam. The fourth to six Kandas explain the characteristics of Sanyasa and Paramahamsa by Sri Yogeeswara Yagnavalkya.
In the first kanda, Brahaspati gives upadesa to Sri Yogeeswara Yagnavalkya. Brahaspati explains what is called "Avimukthav or "Brahma-sathanam" (where Brahman resides) in the body. This Avimuktha is the centre of the forehead and is also called Kurushetram and is to be worshipped all the time. Who ever worships this Avimuktha or brahmasthanam incessantly knowing that this is the centre of the Prana in the body will be given upadesa of Brahman by Sri Rudrar at the time of his death and thereby he reaches Mukthi.
In the second kanda Athri Maharsi inquires with Sri Yogeeswara Yagnavalkya about the Atman which is limitless and which is not visible and how to realize Atman. Sri Yogeeswara Yagnavalkya explains that the Avimuktha resides permanently between Varana and Nasi. Varana prevents (varaythi) the papa done by the indriyas and Nasi destroys all the papas. This is the centre where the two brows and nose meets. This is also the meeting place of this world and devalue. The Brahma Nishtas (persons who have realized Brahman or Atman in their self) always do obeisance to this Avimuktha during the sandya. Whoever has realized such atman shall be qualified to give upadesa about Brahaman or Atman.
In the third kanda the sishyas (students) of Sri Yogeeswara Yagnavalkya inquire him about the Japa by which one can attain or realize Atman and attain Mukthi or Moksha. Sri Yogeeswara Yagnavalkya explains that Satha Rudriya Japam is that Japam by reciting which one can attain moksha. He says it is also called Rudropanisad and consist of one hundred one namas of Sri Rudrar. He also says all the hundred sakhas of Yajur Veda and the other Veda Sakas also praise Sri Rudrar and it is called Satha Rudriyam.
In the fourth Kanda, King Janaka of Videha approaches Sri Yogeeswara Yagnavalkya and inquires him "Hey, Guro you are none other than Bhagavan himself, kindly instruct me about the methods of adopting Sanyasa". Sri Yagnavalkya responds that normally a person becomes sanyasi only after completing all the three stages of life starting with Brahmacharya Ashrama, Gruhasthasrama and Vanaprasthasrama. If a person attains Vairagya he can become sanyasi the moment he achieves the Vairagya regardless of whether he has completed the Veda adhayayan or not or if he does or does not do the aradhana (devotion). Some, before taking up Sanyasa undertake the Prajapthya Ishti. This is not necessarily to be done. For becoming a Sanyasi one should, without any exception forego by vairagya three things in life. They are: Sathva, Rajo and Tamas, he should be above all these three, meaning he should not be affected by these gunas. For such a person to become a Sanyasi, he should pray to Agni with the manthra "Hey ! Agni! Prana, from where the rthvis are born, is your abode and you shine because of the Prana. Having known that, you enter our prana and reach us unto Moksha". With this mantra he should inhale the air and say "the birth place of agni is prana and hence you get absorbed in the prana". He can do this Vraja homam and become Sanyasi.
He can bring this agni from a village or if he is not able to get the agni he can do it with water as water is the embodiment of all devatas.
In the fifth Kanda Athri Rsi inquires with Sri Yogeeswara Yagnavalkya how a brahmana can discard yagnopaveetham when he becomes a Sanyasi. Sri Yagnavalkya said when one becomes a Sanyasi (Gnani who has achieved Vairagya) his Atma itself is the yagnopaveetham. He further elaborates how a person can discard yagnopaveetham and take over Sanyasa. One who has achieved Vairagya can follow the courageous Sanyasis who leave their earthly bodies by entering water or fire or undertake mahaprasthana yathra (which is to travel towards north tirelessly) till the body dissipates by itself. Otherwise a parivraja (sanyasi) who, after shaving his head, clothing himself in barks and without any clothes other than this, and without causing harm to any life even in his thoughts, lives only on alms, becomes eligible for attaining Moksha. If he is not able to undertake such an austerity, due to his ill health or otherwise, he can observe sanyasa by mind or by speech. This path of Sanyasa has been shown by Brahma himself. A Brahma Gnani follows this path.
In the sixth Kanda Sri Yogeeswara Yagnavalkya goes on to explain who are all the well known Brahma Gnanis. They are Smavarthaka, Aruni, Svethakethu, Ripu, Durvasa, Nithagar, Jatabharathar, Dattathreyar, Raivathakar etc. They, the Brahma Gnanis, cannot be easily identified either by sight or by their behaviour. They are not mad but they behave like insane people! They even discard the Dhandam, Kamandalam, vessels etc, hair, poonal etc in the water and devote themselves to the pursuit Atman. Upanisads define a person as Brahma Nishta, if a person lives, without any dress, without any bundles of personal belongings, without even having a begging bowl as they consider their stomach itself as begging bowl, going out at the appropriate time to beg for food with the sole purpose of sustenance of life, treating loss or gain with equanimity, adapting their abode such places as dilapidated buildings, temples, open lawns, snake pit, tree shade, potter's shed, Homa gundam, River, River bed, fissures in mountain rocks, cave, water fall, burning ghats, for that matter any place, without any specific place to live continuously, without engaging themselves sin any profession, without ego, always engaging himself in pure thoughts about Atman, without any personal whims and fancies, foregoing any thing which does not propel him towards moksha, leaving the body mentally even though living. Such a person is called Paramahansa.