etad guhyam aham param
yogam yogesvarat krsnat
saksat kathayatah svayam
vyasa-prasadat—by the mercy of Vyasadeva; srutavan—heard; etat—this; guhyam—confidential; aham—I; param—the supreme; yogam—mysticism; yogesvarat—from the master of all mysticism; krsnat—from Krsna; saksat—directly; kathayatah—speaking; svayam—personally.
By the mercy of Vyasa, I have heard these most confidential talks directly from the master of all mysticism, Krsna, who was speaking personally to Arjuna.
Vyasa was the spiritual master of Sanjaya, and Sanjaya admits that it was by his mercy that he could understand the Supreme Personality of Godhead. This means that one has to understand Krsna not directly but through the medium of the spiritual master. The spiritual master is the transparent medium, although it is true that the experience is direct. This is the mystery of the disciplic succession. When the spiritual master is bona fide, then one can hear Bhagavad-gita directly, as Arjuna heard it. There are many mystics and yogis all over the world, but Krsna is the master of all yoga systems. Krsna's instruction is explicitly stated in Bhagavad-gita-surrender unto Krsna. One who does so is the topmost yogi. This is confirmed in the last verse of the Sixth Chapter. Yoginam api sarvesam.
Narada is the direct disciple of Krsna and the spiritual master of Vyasa. Therefore Vyasa is as bona fide as Arjuna because he comes in the disciplic succession, and Sanjaya is the direct disciple of Vyasa. Therefore by the grace of Vyasa, his senses were purified, and he could see and hear Krsna directly. One who directly hears Krsna can understand this confidential knowledge. If one does not come to the disciplic succession, he cannot hear Krsna; therefore his knowledge is always imperfect, at least as far as understanding Bhagavad-gita is concerned.
In Bhagavad-gita, all the yoga systems, karma-yoga, jnana-yoga and bhakti-yoga, are explained. Krsna is the master of all such mysticism. It is to be understood, however, that as Arjuna was fortunate enough to understand Krsna directly, similarly, by the grace of Vyasa, Sanjaya was also able to hear Krsna directly. Actually there is no difference in hearing directly from Krsna or hearing directly from Krsna via a bona fide spiritual master like Vyasa. The spiritual master is the representative of Vyasadeva also. According to the Vedic system, on the birthday of the spiritual master, the disciples conduct the ceremony called Vyasa-puja.
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