[I]"This Kriyayogaic breathing action is an ancient science. In almost every line of Vedas, Upanishads, Gita and the sastra of Tantrayoga, their esotericism and expedience ave been expounded. The symbol of yoga is reflected in regular worship and in all types of religious actions. At present, just as the deities are concealed under the symbols, similarly under the influence of superficial worship, "The true obeisance/worship/union/soul action" has become concealed.
With regard to the puranic historical viewpoint, Krishna imparted this yoga to Arjuna. Many great souls had practised sadhana in this path of yoga throughout the world and achieved immense spiritual fulfilment. Among them the renowned were Kapil muni, King Janaka, Vyasadeva, Sukhdeva, Patanjala, Socrates, Jesus Christ, Saint John, Saint Paul, Dadudayal, Kabir, Ruhidas, Nanak, Jnaneswar, Tukaram, Ramdas Swami, Ramprasad Sen, Gautama Buddha, Mahavira Jain, etc.. God has stated that when he had once descended in the past, he had imparted this sublime imperishable yoga technique to the Soul-Sun (Surya). Surya had given it to Manu and Manu to Ikshaku. The great sages in this manner handed down this yoga to successive generations; but the yoga has lost its significance due to the onslaught of time.
Thus the still Pranaic PranaKrishna (Literally the term 'Krishna' is an noun but yogically it is a verb. As a verb the term 'Krishna' connotes that a yogi has to cultivate his body-field for annihilating dynamism and attaining stillness), had imparted this immortal yoga to Surya. Prana is Surya (Soul-Sun); the motion of Prana occurs in the Ida and Pingala and this Pingala is known as the sun nerve and Ida is known as the moon nerve.
Therefore the airflow of Prana within the Pingala nerve is Surya. God mentioned to Surya or else that inexpressible state of the still PranaKrishna by entering the nerve of the sun in the form of dynamism, manifested himself dynamically or the sill Pranaic PranaKrishna who reveals himself as the dynamic Prana in the nerve of the sun is the explicit state of yoga. After this Surya imparted this to Manu (Manu means the mind).
When Prana becomes vibratory, this vibratory state acquires a designation of the mind and that mind becomes the expressive state of imperishable yoga in that designation. The still state of air is the state of yoga union. From that still state, vibration evolved and in the sun nerve and mind the state of expression or manifestation of yoga appeared. This is clarified thus, the still Pranalike soul driving vibration was expressed as Surya in the Pingala form, from the Surya to the mind, form the mind to Ikshaku signifying that this sublime eternal yoga became manifest within the external air of the nose.
Amidst the fourfold lives from celibacy to relinquishment of four social orders, the yoga-culture was positively maintained by people belonging to the different strata of society. Almost all the kings of the Raghu dynasty eventually departed abiding by the path of yoga. That sequence in our country was unimpaired till the time of the great poet Kalidasa.
In the first great epic of the Raghu dynasty the evidence of this fact can be underlined from the statement "Yoganantye tanutyajam" Later due to the onslaught of time it became extinct. The avatars preached this sublime yoga sadhana to humanity by again disentangling it from the clutches of time, by amending its austerities and making it suitable for the present spiritually debilitated mankind. This is their supreme bestowal to the whole of humanity and to the universal storehouse of knowledge."