Answer
This is a very good question.
In the first chapter of the Bhagavad-gita, Arjuna expresses deep compassion for his relatives, teachers, and friends, against whom he is expected to fight in the Battle of Kurukshetra. Even before the battle begins, he hesitates to fight and tries to avoid the conflict out of compassion for his kinsmen.
Srila Prabhupada explains in one of his purports that this hesitation is not due to weakness of heart, but rather to Arjuna's soft-hearted nature. As a pure devotee of Krishna, Arjuna naturally possesses great compassion and kindness toward all living beings, especially those who are suffering.
Knowing that those standing on the opposite side of Krishna had no hope of ultimate success, Arjuna felt genuine compassion for them. He wondered why they should have to perish in the battle and questioned whether the war could somehow be avoided.
However, the first chapter also explains that Krishna placed Arjuna under the influence of illusion. This was done for a specific purpose.
Krishna's intention in speaking the Bhagavad-gita was not merely to instruct Arjuna personally. Rather, He intended to enlighten all of humanity. Arjuna served as the medium through whom Krishna delivered this timeless spiritual wisdom.
A pure devotee like Arjuna does not actually require instruction about spiritual truth. Being fully Krishna conscious, he is already enlightened. Therefore, Krishna arranged for Arjuna to temporarily experience bewilderment so that the questions arising in his mind would represent the doubts and confusions experienced by conditioned souls.
When Krishna begins the second chapter by saying, "Do not yield to this petty weakness of heart. Arise and fight," He is addressing Arjuna in his temporarily bewildered condition—a condition that mirrors the state of ordinary human beings.
The Bhagavad-gita explains that every living entity who takes birth in this material world comes under the influence of illusion due to the force of karma. Consequently, everyone begins life in a state of ignorance and misconception.
This illusion can be dispelled only by hearing and following Krishna's instructions. Anyone who sincerely studies and applies the teachings of the Bhagavad-gita can gradually become free from illusion and the influence of material energy.
Thus, Arjuna becomes the representative of all conditioned souls. The questions he asks are the very questions that every sincere seeker should ask in order to attain spiritual realization.
Although Arjuna was temporarily placed in illusion, his position as a pure devotee never changed. His bewilderment was only a divine arrangement to facilitate Krishna's teachings.
At the conclusion of the Bhagavad-gita, Arjuna declares:
"My illusion is now dispelled."
Having heard Krishna's instructions, he returns to his natural state of full Krishna consciousness.
This demonstrates the transformative power of the Bhagavad-gita. Just as Arjuna's temporary illusion was removed by hearing Krishna's words, anyone who properly hears, understands, and follows the teachings of the Bhagavad-gita can become free from illusion and attain true spiritual enlightenment.