Text 21
The Most Confidential Knowledge
[1]  11°
Now this first verse has specific significance. Knowledge ( idam jñānam ) refers to pure devotional service, which consists of nine different activities: hearing, chanting, remembering, serving, worshiping, praying, obeying, maintaining friendship and surrendering everything. By the practice of these nine elements of devotional service one is elevated to spiritual consciousness, Kṛṣṇa consciousness. At the time when one's heart is cleared of the material contamination, one can understand this science of Kṛṣṇa. Simply to understand that a living entity is not material is not sufficient. That may be the beginning of spiritual realization, but one should recognize the difference between activities of the body and spiritual activities by which one understands that he is not the body.
In the Seventh Chapter we have already discussed the opulent potency of the Supreme Personality of Godhead, His different energies, the inferior and superior natures, and all this material manifestation. Now in Chapters Nine and Ten the glories of the Lord will be delineated.
The Sanskrit word  anasūyave  in this verse is also very significant. Generally the commentators, even if they are highly scholarly, are all envious of Kṛṣṇa, the Supreme Personality of Godhead. Even the most erudite scholars write on  Bhagavad-gītā  very inaccurately. Because they are envious of Kṛṣṇa, their commentaries are useless. The commentaries given by devotees of the Lord are bona fide. No one can explain  Bhagavad-gītā , or give perfect knowledge of Kṛṣṇa if he is envious. One who criticizes the character of Kṛṣṇa without knowing Him is a fool. So such commentaries should be very carefully avoided. For one who understands that Kṛṣṇa is the Supreme Personality of Godhead, the pure and transcendental Personality, these chapters will be very beneficial.
TEXT 2
राजविद्या राजगुहं पवित्रमिदमुत्तमम् । 
    प्रत्यक्षावगमं धर्म्यं सुसुखं कर्तुमव्ययम् ॥ २ ॥
rāja-vidyā rāja-guhyaṁ pavitram idam uttamam pratyakṣāvagamaṁ dharmyaṁ susukhaṁ kartum avyayam
rāja-vidyā —the king of education;  rāja-guhyam —the king of confidential knowledge;  pavitram —the purest;  idam —this;  uttamam —transcendental;