बन्धुरात्माऽऽत्मनस्तस्य येनात्मैवात्मना जितः।
अनात्मनस्तु शत्रुत्वे वर्तेतात्मैव शत्रुवत्।।6.6।।
।।6.6।। जिसने आत्मा (इंद्रियोंआदि) को आत्मा के द्वारा जीत लिया है उस पुरुष का आत्मा उसका मित्र होता है परन्तु अजितेन्द्रिय के लिए आत्मा शत्रु के समान स्थित होता है।।
To whom is the mind a dear friend has been mentioned by Lord Krishna in this verse. Here the word atma should be understood as being the mind and the word atmana as being the living entity. So the meaning is that the atmana or living entity achieves success by the strength of the atma or mind. In the Brahmavaivartaka Purana states: That the condition of the mind is the sole reason for human beings to be liberated from the material existence or contrarily incarcerated in the material existence. The mind should elevate a human being and not be a source of delusion and distress for the mind has the propensity to be the best friend or the worst enemy of this there is no doubt. When with diligence and determination the mind is well governed it is like a best friend and then there are no other enemies. Therefore one should amiably govern their mind by Vedic knowledge and with devotion to the Supreme Lord. The word atmana refers to one whose mind is fixed and unconquerable. But even so if the mind is not directed towards devotion to the Supreme Lord it is not likely to be helpful in the same way as having a servant who does no work is like not having a servant at all and soon the mind will become antagonistic to restraint and then an enemy. Now begins the summation. The individual consciousness elevates itself by the mercy of the ultimate consciousness. Lord Krishna is perpetually the best friend and well-wisher of the righteous and spiritual beings but a perpetual enemy to the perpetrators of evil and unrighteousness. This means that to one who is devoted to the Supreme Lord Krishna or any of His authorised incarnations the mind acts as a dear friend by His grace; but for all others the mind is like an enemy. In the end of the verse it is indicated that the Supreme Being aides within such a person.
