There are five basic relationships a devotee might have with the Lord; namely in the neutral stage (sānta-rasa), which is the stage of awe and reverence. Knowing that God is Great. Then there are four transcendental mellows (rasas); servitude (dāsya), friendship (sakhya), parental affection (vātsalya) and conjugal love (śṛṅgāra).
Kṛṣṇa and Arjuna are related in friendship.
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, we have not only forgotten the Supreme Lord, but we have forgotten our eternal relationship with the Lord. Every living being, out of 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. (from Introduction to Bhagavad-gita As It Is)
The following verse is one of my most favorite from the Bhagavad-gita As It Is.
I have in the past addressed You as “O Kṛṣṇa,” “O Yādava,” “O my friend,” without knowing Your glories. Please forgive whatever I may have done in madness or in love. I have dishonored You many times while relaxing or while lying on the same bed or eating together, sometimes alone and sometimes in front of many friends. Please excuse me for all my offenses.
I find this verse to be a beautiful expression of what is Bhakti Yoga. It is a personal loving exchange with the Lord. There are two ways to approach the Lord. One can approach the Lord with awe and reverence (sānta-rasa), or with a more personal approach; love and affection.
Kṛṣṇa’s devotees relate to Kṛṣṇa in various relationships.. Kṛṣṇa and Arjuna are related in friendship. As the father tolerates, or the husband or master tolerates, so Kṛṣṇa tolerates. Very Beautiful!
Bhagavad-gita As It Is Texts 40-45 More
The Hare Krishna Movement 