Arjuna was the most intimate friend of Kṛṣṇa, and Kṛṣṇa was directly guiding him on the chariot; but in spite of all these credits, if Arjuna abandoned the battle he would be committing an infamous act. Therefore Kṛṣṇa said that such an attitude in Arjuna did not fit his personality. Arjuna might argue that he would give up the battle on the grounds of his magnanimous attitude for the most respectable Bhīṣma and his relatives, but Kṛṣṇa considered that sort of magnanimity mere weakness of heart. Such false magnanimity was not approved by any authority. Therefore, such magnanimity or so-called nonviolence should be given up by persons like Arjuna under the direct guidance of Kṛṣṇa.
(Bhagavad-Gita----2:3----purport).

Respectable superiors like Bhīṣma the grandfather and Droṇācārya the teacher are always worshipable. Even if they attack, they should not be counterattacked. It is general etiquette that superiors are not to be offered even a verbal fight. Even if they are sometimes harsh in behavior, they should not be harshly treated. Then, how is it possible forArjuna to counterattack them? Would Kṛṣṇa ever attack His own grandfather, Ugrasena, or His teacher, Sāndīpani Muni? These were some of the arguments offered by Arjuna to Kṛṣṇa.
(Bhagavad-Gita----2:4----purport).

Under the circumstances, they have lost the respectability of teachers. But Arjuna thinks that nevertheless they remain his superiors, and therefore to enjoy material profits after killing them would mean to enjoy spoils tainted with blood.
(Bhagavad-Gita----2:5----purport).

All these considerations by Arjuna definitely proved that not only was he a great devotee of the Lord but he was also highly enlightened and had complete control over his mind and senses. His desire to live by begging, although he was born in the royal household, is another sign of detachment. He was truly virtuous, as these qualities, combined with his faith in the words of instruction of Śrī Kṛṣṇa (his spiritual master), indicate. It is concluded that Arjuna was quite fit for liberation. Unless the senses are controlled, there is no chance of elevation to the platform of knowledge, and without knowledge and devotion there is no chance of liberation. Arjuna was competent in all these attributes, over and above his enormous attributes in his material relationships.
(Bhagavad-Gita----2:6----purport).

He offers himself to Kṛṣṇa as a disciple. He wants to stop friendly talks. Talks between the master and the disciple are serious, and now Arjuna wants to talk very seriously before the recognized spiritual master. Kṛṣṇa is therefore the original spiritual master of the science of Bhagavad-gītā, and Arjuna is the first disciple for understanding the Gītā. How Arjuna understands the Bhagavad-gītā is stated in the Gītā itself. And yet foolish mundane scholars explain that one need not submit to Kṛṣṇa as a person, but to "the unborn within Kṛṣṇa."
(Bhagavad-Gita----2:7----purport).

Although Arjuna was putting forward so many arguments based on knowledge of the principles of religion and moral codes, it appears that he was unable to solve his real problem without the help of the spiritual master, Lord Śrī Kṛṣṇa. He could understand that his so-called knowledge was useless in driving away his problems, which were drying up his whole existence; and it was impossible for him to solve such perplexities without the help of a spiritual master like Lord Kṛṣṇa.
(Bhagavad-Gita----2:8----purport).

Dhṛtarāṣṭra must have been very glad to understand that Arjuna was not going to fight and was instead leaving the battlefield for the begging profession. But Sañjaya disappointed him again in relating that Arjuna was competent to kill his enemies (parantapaḥ). Although Arjuna was, for the time being, overwhelmed with false grief due to family affection, he surrendered unto Kṛṣṇa, the supreme spiritual master, as a disciple.
(Bhagavad-Gita----2:9----purport).

The same Vedic truth given to Arjuna is given to all persons in the world who pose themselves as very learned but factually have but a poor fund of knowledge. The Lord says clearly that He Himself, Arjuna and all the kings who are assembled on the battlefield are eternally individual beings and that the Lord is eternally the maintainer of the individual living entities both in their conditioned and in their liberated situations.
(Bhagavad-Gita----2:12----purport).

The Supreme Personality of Godhead is the supreme individual person, and Arjuna, the Lord's eternal associate, and all the kings assembled there are individual eternal persons. It is not that they did not exist as individuals in the past, and it is not that they will not remain eternal persons. Their individuality existed in the past, and their individuality will continue in the future without interruption. Therefore, there is no cause for lamentation for anyone.
(Bhagavad-Gita----2:12----purport).

The stars can be compared to the living entities and the sun or the moon to the Supreme Lord. The individual fragmental spirit soul is represented by Arjuna, and the Supreme Soul is the Personality of Godhead Śrī Kṛṣṇa. They are not on the same level, as it will be apparent in the beginning of the Fourth Chapter. If Arjuna is on the same level with Kṛṣṇa, and Kṛṣṇa is not superior to Arjuna, then their relationship of instructor and instructed becomes meaningless. If both of them are deluded by the illusory energy (māyā), then there is no need of one being the instructor and the other the instructed. Such instruction would be useless because, in the clutches of māyā, no one can be an authoritative instructor. Under the circumstances, it is admitted that Lord Kṛṣṇa is the Supreme Lord, superior in position to the living entity, Arjuna, who is a forgetful soul deluded by māyā.
(Bhagavad-Gita----2:13----purport).

One of the birds (the individual atomic soul) is eating the fruit of the tree, and the other bird (Kṛṣṇa) is simply watching His friend. Of these two birds—although they are the same in quality—one is captivated by the fruits of the material tree, while the other is simply witnessing the activities of His friend. Kṛṣṇa is the witnessing bird, and Arjuna is the eating bird. Although they are friends, one is still the master and the other is the servant. Forgetfulness of this relationship by the atomic soul is the cause of one's changing his position from one tree to another, or from one body to another. The jīva soul is struggling very hard on the tree of the material body, but as soon as he agrees to accept the other bird as the supreme spiritual master—as Arjuna agreed to do by voluntary surrender unto Kṛṣṇa for instruction—the subordinate bird immediately becomes free from all lamentations.
(Bhagavad-Gita----2:22----purport).

In the Varāha Purāṇa, the living entities are described as separated parts and parcels of the Supreme. They are eternally so, according to the Bhagavad-gītā also. So, even after being liberated from illusion, the living entity remains a separate identity, as is evident from the teachings of the Lord to Arjuna. Arjuna became liberated by the knowledge received from Kṛṣṇa, but he never became one with Kṛṣṇa.
(Bhagavad-Gita----2:23----purport).

So, in any case, whether Arjuna accepted the Vedic conclusion that there is an atomic soul or he did not believe in the existence of the soul, he had no reason to lament. According to this theory, since there are so many living entities generating out of matter every moment, and so many of them are being vanquished every moment, there is no need to grieve for such incidents. If there were no rebirth for the soul, Arjuna had no reason to be afraid of being affected by sinful reactions due to his killing his grandfather and teacher. But at the same time, Kṛṣṇa sarcastically addressed Arjuna as mahā-bāhu, mighty-armed, because He, at least, did not accept the theory of the vaibhāṣikas, which leaves aside the Vedic wisdom. As a kṣatriya, Arjuna belonged to the Vedic culture, and it behooved him to continue to follow its principles.
(Bhagavad-Gita----2:26----purport).

Arjuna was a famous fighter, and he attained fame by fighting many great demigods, including even Lord Śiva. After fighting and defeating Lord Śiva in the dress of a hunter, Arjuna pleased the lord and received as a reward a weapon called pāśupata-astra. Everyone knew that he was a great warrior. Even Droṇācārya gave him benedictions and awarded him the special weapon by which he could kill even his teacher. So he was credited with so many military certificates from many authorities, including his adopted father Indra, the heavenly king.
(Bhagavad-Gita----2:33----purport).

Lord Kṛṣṇa now directly says that Arjuna should fight for the sake of fighting because He desires the battle. There is no consideration of happiness or distress, profit or gain, victory or defeat in the activities of Kṛṣṇa consciousness. That everything should be performed for the sake of Kṛṣṇa is transcendental consciousness; so there is no reaction to material activities. He who acts for his own sense gratification, either in goodness or in passion, is subject to the reaction, good or bad. But he who has completely surrendered himself in the activities of Kṛṣṇa consciousness is no longer obliged to anyone, nor is he a debtor to anyone, as one is in the ordinary course of activities.
(Bhagavad-Gita----2:38----purport).

There are three considerations here: prescribed duties, capricious work, and inaction. Prescribed duties are activities enjoined in terms of one's acquired modes of material nature. Capricious work means actions without the sanction of authority, and inaction means not performing one's prescribed duties. The Lord advised that Arjuna not be inactive, but that he perform his prescribed duty without being attached to the result. One who is attached to the result of his work is also the cause of the action. Thus he is the enjoyer or sufferer of the result of such actions.
(Bhagavad-Gita----2:47----purport).

To understand one's actual position as the eternal servitor of Kṛṣṇa, without falsely claiming this material body to be oneself and without falsely claiming proprietorship over anything in the world, is the perfect stage of Kṛṣṇa consciousness. One who is situated in this perfect stage knows that because Kṛṣṇa is the proprietor of everything, everything must be used for the satisfaction of Kṛṣṇa. Arjuna did not want to fight for his own sense satisfaction, but when he became fully Kṛṣṇa conscious he fought because Kṛṣṇa wanted him to fight. For himself there was no desire to fight, but for Kṛṣṇa the same Arjuna fought to his best ability. Real desirelessness is desire for the satisfaction of Kṛṣṇa, not an artificial attempt to abolish desires.
(Bhagavad-Gita----2:71----purport).

The living entity cannot be happy independent of the cooperation of the Supreme Lord, because the eternal constitutional position of the living entity is to become subordinate to the desires of the Lord. Arjuna was therefore ordered by Śrī Kṛṣṇa to fight as if the Lord were his military commander. One has to sacrifice everything for the good will of the Supreme Lord, and at the same time discharge prescribed duties without claiming proprietorship. Arjuna did not have to consider the order of the Lord; he had only to execute His order. The Supreme Lord is the soul of all souls; therefore, one who depends solely and wholly on the Supreme Soul without personal consideration, or in other words, one who is fully Kṛṣṇa conscious, is called adhyātma-cetas. Nirāśīḥ means that one has to act on the order of the master but should not expect fruitive results.
(Bhagavad-Gita----3:30----purport).

Accepting that before the birth of Manu the Gītā was spoken by the Lord to His disciple the sun-god Vivasvān, a rough estimate is that the Gītā was spoken at least 120,400,000 years ago; and in human society it has been extant for two million years. It was respoken by the Lord again to Arjuna about five thousand years ago. That is the rough estimate of the history of the Gītā, according to the Gītā itself and according to the version of the speaker, Lord Śrī Kṛṣṇa. It was spoken to the sun-god Vivasvān because he is also a kṣatriya and is the father of all kṣatriyas who are descendants of the sun-god, or the sūrya-vaṁśa kṣatriyas.
(Bhagavad-Gita----4:1----purport).