Bhagvad Gita is especially meant for the devotees

From The Introduction of Bhgavad Gita As it is...

He tells Arjuna that He is relating this supreme secret to him because Arjuna is His devotee and His friend. The purport of this is that Bhagavad-gītā is a treatise which is especially meant for the devotee of the Lord. There are three classes of transcendentalists, namely the jñānī, the yogī and the bhakta, or the impersonalist, the meditator and the devotee. Here the Lord clearly tells Arjuna that He is making him the first receiver of a new paramparā(disciplic succession) because the old succession was broken. It was the Lord’s wish, therefore, to establish another paramparā in the same line of thought that was coming down from the sun-god to others, and it was His wish that His teaching be distributed anew by Arjuna. He wanted Arjuna to become the authority in understanding the Bhagavad-gītā. So we see that Bhagavad-gītā is instructed to Arjuna especially because Arjuna was a devotee of the Lord, a direct student of Kṛṣṇa, and His intimate friend. Therefore Bhagavad-gītā is best understood by a person who has qualities similar to Arjuna’s. That is to say he must be a devotee in a direct relationship with the Lord. As soon as one becomes a devotee of the Lord, he also has a direct relationship with the Lord. That is a very elaborate subject matter, but briefly it can be stated that a devotee is in a relationship with the Supreme Personality of Godhead in one of five different ways:

1.  One may be a devotee in a passive state;

2.  One may be a devotee in an active state;

3.  One may be a devotee as a friend;

4.  One may be a devotee as a parent;

5.  One may be a devotee as a conjugal lover.

Arjuna was in a relationship with the Lord as friend. Of course there is a gulf of difference between this friendship and the friendship found in the material world. This is transcendental friendship, which cannot be had by everyone. Of course everyone has a particular relationship with the Lord, and that relationship is evoked by the perfection of devotional service. But in the present status of our life, not only have we forgotten the Supreme Lord, but we have forgotten our eternal relationship with the Lord. Every living being, out of the many, many billions and trillions of living beings, has a particular relationship with the Lord eternally. That is called svarūpa. By the process of devotional service, one can revive that svarūpa, and that stage is called svarūpa-siddhi – perfection of one’s constitutional position. So Arjuna was a devotee, and he was in touch with the Supreme Lord in friendship.