INTRODUCTION TO BHAGAVAD-GITA AS IT IS.
Now, in the Fourth Chapter, the Lord tells Arjuna that this Yoga system of The Bhagavad Gita was first spoken to the Sun-god:
The Blessed Lord said: I instructed this imperishable science of Yoga to the Sun-god, Vivasvan, and Vivasvan instructed it to Manu, the father of Mankind, and Manu in turn instructed it to Ikshaku. This supreme science was thus received through the chain of disciplic succession, and the saintly kings understood it in that way. But in the course of time the succession was broken, and therefore the science, as it is, appears to be lost.
Arjuna was neither a great scholar nor a Vedantist, but a great soldier. A soldier is not supposed to be scholarly, and so Arjuna was selected to understand The Bhagavad Gita because of one qualification only: He was a devotee of the Lord. This indicates that The Bhagavad Gita is especially meant for the devotee of the Lord...