Question: Lord Krishna said that the relationship between individual soul and the Super Soul is eternal. That can be friendship, parenthood or conjugal relationship. Does that mean we have an eternal body long time ago in the spiritual world? Or the body and relationship with Lord will be decided by the devotional practice of all the lifetimes?
Answer by Romapada Swami: I am going to give you a short answer now, and a longer answer after some time.
There is an eternal connection between the individual soul (or atma) and the Supersoul (Paramatma), much like a spark is related to the fire from whence it comes.
Such a relationship is passive, however, or neutral. It is not inherently a service-oriented relationship; in contrast, friendship, parenthood or conjugal relationship are service-oriented, thus the jiva in devotion sees the Supreme as Bhagavan.
We know that Paramatma is in our heart (BG 13.18), that He is guiding us + witnessing in a neutral way all of our desires and actions (BG 15.15). He is also rewarding us our respective consequences; by so doing He is a friend to us in one sense, as stated in BG 5.29.
However, the way that you are refering to friendship in the question above clearly indicates interaction with the Bhagavan feature of Krishna.
We have an eternal spiritual body even now, yet it is dormant due to our covered state of consciousness. Consider, for comparison sake, the dormant life and dormant consciousness within an unsprouted seed. When sprouted, life awakens, as does consciousness. Similarly, our spiritual form (svarupa) awakens via the process of sadhana-bhakti, as it did with Narada Muni (See SB 1.6.27).
Our svarupa is eternal. Whatever our eternal spiritual form is, it will be revealed to us in course of time, as we follow the principles of sadhana-bhakti.