Bhakto 'si me sakhā ceti rahasyaṁ hy etad uttamam; "O My dear Arjuna, I am just trying to speak to you Bhagavad-gītā because you have got an exceptional qualification which others haven't got." And what is that exceptional qualification? Here it is clearly mentioned, bhakto 'si. Bhakto 'si. Bhakto 'si means "You are My devotee. You know that I am the Supreme Personality of Godhead, and therefore you have surrendered yourself unto Me, accepted Me, Myself, as the spiritual master. You know. You are My devotee."
Now, here we have to understand that unless one is devotee of Lord Kṛṣṇa it is not possible for him to understand what is Bhagavad-gītā. It is not possible. Nobody can understand Bhagavad-gītā unless he is a devotee of Lord Kṛṣṇa. That is the first qualification. It is clearly said here. You cannot go beyond Bhagavad-gītā. If you want to understand Bhagavad-gītā, you cannot take help of other method. You have to take the help as it is mentioned in the Bhagavad-gītā.