The sannyasin treads the nivritti marga (the path of return to the source). This path is widely called the inward path, in contrast to the pravritti marga (the path of outward, worldly activity). Actually this term 'inward path' is a misnomer. A sannyasin doesn't concern himself only with his inner being; he also acts in the world. In fact, he acts more powerfully in the outside world. The inner path really means that the inner and outer worlds are merged and harmonized so that there are no longer any rigid boundaries. The inner path doesn't mean that one is concerned with only the psyche; this is the psychic or ida path. This path leads to psychic powers but not necessarily spiritual realization. The inner path of the sannyasin is the path of sushumna, perfect balance between the ida and pingala, the inner and outer realms.
The outer path (pingala) that most people tread leads to frustration and confusion. It implies total absorption in the external, material world. The ida path of complete interest in the psyche and the awakening of psychic powers etc. also leads to delusion, but of a different type. The inner path of the sushumna leads to realization. It leads to bliss and harmony. The ida and the pingala paths lead to bondage. It is the sushumna path, the inner path, that will lead an aspirant to complete freedom.
There are many scriptures which have given extensive instructions regarding the path a sannyasin must tread. For example in the Seng T'san it said that:
The perfect path is only difficult
for those who pick and choose;
Do not like, do not dislike; all will then be clear.
Make a hair's breadth difference,
and heaven and earth are set apart.
If you want the truth to stand clear before you,
never be for' and 'against'.
The struggle between 'for' and 'against'
is the mind's worst problem and disease.
This gives an indication to those who sincerely want to walk on the path to perfection. This path is often described as a razor's edge and indeed it is. It cannot be classified in logical terms, as this quotation of Mumonkan indicates:
The great path has no gates,
Yet thousands of roads enter it.
When one passes through this gateless gate,
He walks freely between heaven and hell.
It is along this mysterious path that a sannyasin must tread. It can only be understood as he travels along its narrow confines in just the same way that a traveller can only know the scenery on the wayside by actually walking along the road for himself.
In India, the path of sannyasa is traditionally associated with the cosmic mantra Aum. The main sadhana (spiritual practice) of many sannyasins is continuous remembrance of Aum. It is even sometimes said a sannyasin needs no other practice. In the Mahanarayana Upanishad it says: The sannyasin should concentrate all his thoughts on Aum. This syllable Aum is the essence of the Upanishads and its secrets are carefully guarded from those who are unfit by the devas (astral beings). He who continually reflects on the meaning of Aum after taking initiation into sannyasa will attain the Supreme. This comes through knowledge of the secrets of Aum. (v.80:18)
The Narada Parivrajaka Upanishad says:Apart from Aum no scriptures and religions need to be studied. (v.5:20)
The importance of Aum in a sannyasin's life is reiterated in a large number of other scriptures, including the Mandukya Upanishad. Other mantras can also be used. In the Kularnava Tantra, continuous remembrance and reflection on Soham is recommended. The purpose of the mantra is to make the mind one-pointed. Continuous remembrance brings this about; the whole mind flows in one direction like the river Ganges. Continuous reflection on the meaning of Soham brings about illumination, revelation of its deepest implications. The process is clearly described in the Mahanarayana Upanishad as follows: ... by dedication (to the practice) comes mental power. From mental power comes sense withdrawal (pratyahara); this makes deep reflection possible. From reflection comes calmness of mind; this leads to illumination or conclusive experience of truth. This illumination intensifies remembrance of truth. This remembrance produces continuous remembrance. Continuous remembrance leads to unbroken, direct realization of truth. By such realization, a person lives in Atman. (v.79:15)
In Alice in Wonderland it is said in the following way:
Begin at the beginning
and go on till you come to the end;
The sannyasin has to make his mind powerful and one-pointed. To do this, he can try to unceasingly remember a mantra. He can make his mind one-pointed through karma yoga, bhakti yoga, jnana yoga or any other form of yoga. This is called abhyasa (yogic practice). At the same time, he has to gradually awaken the inner feeling of vairaghya (renunciation). This combination makes the mind calm yet one-pointed.
These two words, vairaghya and abhyasa, actually sum up the path of sannyasa. They are the two sides of the ladder by which a sannyasin, or any other spiritual aspirant, climbs and ascends to wisdom. Remember these two words carefully... but much better make them an integral part of your life.
While treading the path, the sannyasin must also have constant aspiration. This is explained beautifully by St Mattew:
Ask and it shall be given to you; seek and ye shall find; knock and it shall be opened unto you. For everyone that asketh, receiveth; and he that seeketh, findeth; and to him that knocked, it shall be opened.
Without this aspiration, the gates of the gateless path will not be opened. So the sannyasin should have continuous aspiration to know the truth; he should practice yoga, and he should slowly awaken detachment. This is the path of a sannyasin.