Madhudviṣa: "This supreme science was thus received through the chain of disciplic succession and the saintly kings understood it in that. But in the course of time the succession was broken, and therefore the science as it is appears to be lost."
Three: "That very ancient science of the relationship with the Supreme is today told by Me to you. Because you are My devotee as well as My friend, therefore you can understand the transcendental mystery of this science."
Purport: "There are two classes of men, namely the devotee and the demon. The Lord accepted Arjuna as the recipient of this great science owing to his being a devotee of the Lord. But for the demons it is not possible to understand this great, mysterious science. There are a number of editions of this great book of knowledge and some of them are commented upon by the devotees, and some of them are commented upon by the demons. Commentary by the devotees is real, whereas that of the demons is useless."
Prabhupāda: Because it is said here that "that very ancient science of the relationship with the Supreme is today told by Me to you because you are My devotee," so this transcendental science cannot be understood simply by academic education. It is not possible. There is a secret. Just like in the ordinary educational field, nobody is allowed to study law unless he is a graduate of the degree college. At least in India that is the law. Nobody can be admitted in the law college unless he is a graduate because he will not be able to understand.
Similarly, in the Vedas it is also said, "Unless one has acquired brahminical qualifications, he should not study Vedas." So in every department, if you want to take education in a particular line, you have to qualify yourself to enter that school or college. Similarly, if you want to study Bhagavad-gītā, then you have to become a devotee. Simply academic educational qualification will not help you, because it was spoken to the devotee.
Kṛṣṇa says that "That very ancient science of relationship with the Supreme is today told by Me to you because you are My devotee." So how the nondevotees can understand? Nondevotee cannot understand. And who is a devotee? And who is a nondevotee? Devotee means one who accepts the supremacy of the Supreme Lord, and he is convinced, his eternal relationship with God.
Just like Lord Jesus Christ. He was threatened with death punishment. He was crucified. Still, he was convinced, his relationship with God. Here is a devotee, example of devotee. Devotee means he is firmly convinced about his relationship with God. And what is that relationship? That relationship is on the basis of love. The devotee loves God, and God loves devotee. This is the only relationship. That's all. God is after devotee, and devotee after God. This is relationship.
So one has to establish this relationship. Just like Arjuna is in relationship with Kṛṣṇa as a friend, similarly, you can be in relationship with God as a lover. You can be in relationship with God as master and servant. You can be in relationship with God as father and son. There are so many relationships. As we have got relationship within this material world, this is only perverted reflection of that five relationship with God. But we have forgotten that. This Kṛṣṇa consciousness movement is to revive that consciousness. It is nothing new. To forget God means that is abnormal condition, and to have relationship with God is normal condition. So Kṛṣṇa consciousness means to be reestablished in our normal condition of life. Go on. "Arjuna is..."
Madhudviṣa: "Arjuna is recognized by the Lord as a devotee. Therefore one who follows the line of Arjuna in understanding the Gītā will derive benefit from it. Otherwise one will simply waste his valuable time in reading commentaries. Arjuna accepts Śrī Kṛṣṇa as the Supreme Personality of Godhead, and any commentary of the Gītā following in the footsteps of Arjuna is real devotional service to the cause of this great science. But the demons do not accept Lord Kṛṣṇa as He is. The demons concoct something out of their imagination about Kṛṣṇa's instructions. Here is a warning regarding such misleading paths. One should try to follow the disciplic succession from Arjuna and thus be benefited by this great science of the Śrīmad-Bhagavad-gītā."
Prabhupāda: Yes. If we want to study Bhagavad-gītā, then we follow the principles. Just like we have explained this in the introduction, that when you take a bottle of medicine, there is some direction that "Two tablets, twice in a day after meals." So you have to follow the instruction. Then you get benefit. You cannot take any instruction about taking that medicine from a friend or from an expert educationist. No. You have to take direction only from the physician. He is the expert in that line.
Similarly, here is the direction, the bottle of Bhagavad-gītā. Kṛṣṇa says, "It should be understood by the devotee, or you have to understand Bhagavad-gītā from a devotee." This is the direction of this medicinal bottle. How you can go otherwise? Then you will get the benefit. That is explained.