हठयोग प्रदीपिका (योगी स्वात्माराम - ज्योत्स्ना टीका सहित सटीक)

8 HAṬHAYOGAPRADĪPIKĀ
He should begin Prāṇāyāma only with the guidance of his Guru.’
The work called Rāja-yoga also states: ‘Kaivalya is not to be got
by any amount of study of the Veda-s, Śāstra-s and Tantra-s,
without the guidance of a Guru.’ In the Skanda-purāṇa it is said:
‘The eight stages of Yoga are to be learnt only from a competent
Guru.’ And Sureśvarācārya declares that only through the Guru
can the eightfold Yoga be learnt. The śruti says: ‘The Mahātman-s
reveal those things only to him who has a deep devotion towards
his Guru as well as to God. Only he who has an Ācārya or Guru
knows.’ The various standard books on Yoga are, I think, meant
not so much for beginners and students, as for Guru-s to use as
guide-books to regulate their pupils’ training. In Haṭha-yoga,
where a mistake may end in death or insanity, it is absolutely
necessary to have a Guru, who has passed successfully through
the course, who can see clearly through the system, and observe
the effects of the various processes and modify them accordingly.
15. Yoga fails by the six [causes]—over-eating,
over-exertion, excessive talk, the observance of [un-
suitable] disciplines, promiscuous company and un-
steadiness.
The disciplines referred to are bathing in cold water early in
the morning, eating only at night and fasting frequently.
16. Yoga succeeds by the six [qualifications]—
zeal, bold determination, courage, true knowledge,
firmness [of belief in the words of the Guru] and re-
nunciation of the company of [unsuitable] people.
[To do no harm, to speak the truth, to refrain
from taking what belongs to another, to preserve
continence, to practise forbearance, to have fortitude, to
be merciful, to be straightforward, to be moderate in
diet and to be pure—these ten constitute Yama.]