बन्धुरात्माऽऽत्मनस्तस्य येनात्मैवात्मना जितः।
अनात्मनस्तु शत्रुत्वे वर्तेतात्मैव शत्रुवत्।।6.6।।
6.6. The self is the friend of that Self by Which the self has been verily subdued; but [in the case of] a person with an unsubdued self, the self alone would abide in enmity like an enemy.
6.5-6 Uddharet etc. Bandhuh etc. In this [path] there is no other means excepting the self i.e. nothing but ones mind. Indeed the subdued mind is a friend and it lifts up [the Self] from the highly dreadful cycle of birth and death. But the unsubdued one does the act of enmity as it throws [the Self] down in the horrible hell. The characteristic mark of the subdued-minded man is this :
Bandhuraatmaa’tmanastasya yenaatmaivaatmanaa jitah; Anaatmanastu shatrutwe vartetaatmaiva shatruvat.
bandhuḥ—friend; ātmā—the mind; ātmanaḥ—for the person; tasya—of him; yena—by whom; ātmā—the mind; eva—certainly; ātmanā—for the person; jitaḥ—conquered; anātmanaḥ—of those with unconquered mind; tu—but; śhatrutve—for an enemy; varteta—remains; ātmā—the mind; eva—as; śhatru-vat—like an enemy