Did we not discuss that all paths in reality merge into worship of Guru? For this reason, Mother Goddess Paravati sought to know the significance of the word Guru and the essence behind worship of Guru.
A Guru necessarily has to clarify the doubts of his sincere disciple. Therefore, Shiva had to preach Her. In heaven (Deva loka) known as Kailasa, which is the residence of Lord Shiva, in the presence of many eminent saints and yogis, this holy conversation, which in reality was for the welfare of the saints and the spiritual aspirants, took place between the primordial couple, Shiva and Parvati.
It was Dattatreya who brought this principle of Guru to earth! Therefore, He is addressed as ‘Guru mārga pravartaka (one who directs people into the Guru path)’. He introduced the concept of Guru, emphasized upon the necessity of spiritual Guru in one’s life, explained the principle and essence of Guru, the method of worshipping the Guru etc. to humans.
He is therefore addressed as Adi Guru, Deva-guru, Paramaguru, Parātpara Guru, Parampara Guru, Parameshti Guru etc. We therefore offer the first salutation to Him.
In a much later period came Maharishi Veda Vyasa. In his Puranas, he preached Datta Sadguru principle and in His Skanda Purana, he conveyed this concept of Guru as a conversation between Shiva and Parvati. Even Śuka Maharishi explained this concept of Guru to Vyasa. How did Śuka obtain this knowledge of Guru principle?
Once when Parvati asked Shiva to teach her Supreme Essence, Shiva asked her to verify that there was no other living being within these sacred environs. Parvati thoroughly checked all directions and reported that they both were alone in that premises. In reality, there was an egg in that vicinity. Its parents had died earlier.
As Shiva was preaching, the egg hatched and a little bird emerged from it. Shiva said to Parvati- “you said that there was no one in this area. Now from where is this sound coming? What is that bird doing there?”
Parvati replied- “O Lord! Kindly do not focus your angry gaze upon it. When you had ordered me to check the surroundings, only the egg was there. Egg is not a living being. Your grace alone has caused the egg to hatch at this point of time”.
This bird Śuka flew to Maharishi Vyasa and preached to him the Bhagavata tattva and Guru tattva.
After Vyasa, Adi Shankara bhagavadpāda preached in great detail the essence of Guru in various occasions.