9.1 idam this, tu indeed, tē to thee, guhyatamam greatest secret, pravakṣyāmi (I) shall declare, anasūyavē to one who does not cavil, jñānam knowledge, vijñānasahitam combined with experience, yat which, jñātvā having known, mōkṣyasē thou shalt be free, aśubhāt from evil.

Commentary:
Idam (this) alludes to knowledge of the Self.Jnana: Theoretical knowledge of rahman through the study of the Upanishads, also known as Paroksha rahma Jnana.Vijnana: Direct intuitive perception of rahman or Atma-Sakshatkara, also known as Aparoksha rahma Jnana.This alone forms the direct means of attaining to liberation from evil or the bondage of Samsara, freedom from birth and death.The knowledge of the Self is the most profound secret. It can hardly be described in words. It can be realised only through direct experience or spiritual intuition. Atman or rahman or the self-luminous, eternal, Supreme Purusha is ever shining in the chambers of the hearts of men. Throughout the ages there have always been a few who have trodden the spiritual path and found out this secret or the spiritual treasure of the precious pearl of the Self. Knowledge of the Self is the only direct means for attaining liberation, Karma Yoga purifies the heart and leads to the dawn of the knowledge of the Self.Lord Krishna says, "O Arjuna, I shall teach you this profoundest secret knowledge combined with realisation as you are free from jealousy." From this we can clearly understand that freedom from jealousy is an important alification for an aspirant. Knowledge can only dawn in a mind which is free from all forms of jealousy which causes great distraction of the mind and produces intense heart-burning. Matsarya (malicious envy), Irshya (jealous of others' prosperity or happiness) and Asuya (envious or indignant over the merits of another) are all varieties of jealousy. If you superimpose evil alities on a virtuous man who really does not possess these alities on a virtuous man who really does not possess these alities and speak ill of him, this is jealousy (Asuya). To behold evil or to look at a person with the fault-finding evil eye, and to see evil in him who is free from any kind of fault and who is virtuous is Asyua. Jealousy is only petty-mindedness. This is a modification of ignorance. It can be eradicated by eniry of the nature of the Self and cultivating its opposite alities, viz., nobility, broad and universal tolerance, magnanimity and large-heartedness.To thee who does not carp or cavil: This implies that Arjuna was endowed with all the virtues of a disciple such as straightforwardness, self-control, restraint of the senses, serenity of mind, discrmination, dispassion, etc. This is the Upalakshana (the truth alluded to where only a part is stated) and Asuya is the Upalakshaka (the hint which alludes to the Upalakshana).