bandhur ātmātmanas tasya yenātmaivātmanā jitaḥ
anātmanas tu śhatrutve vartetātmaiva śhatru-vat||6||

Meaning : For one who has conquered the mind, the mind becomes the best friend. But for one who has failed to control it, the mind acts as the worst enemy. Thus, the self is both friend and foe depending on one’s inner discipline.