Bhagavad Gita, Chapter 6, Verse 6

बन्धुरात्मात्मनस्तस्य येनात्मैवात्मना जितः । अनात्मनस्तु शत्रुत्वे वर्तेतात्मैव शत्रुवत्

bandhurātmātmanastasya yenātmaivātmanā jitaḥ | anātmanastu śatrutve vartetātmaiva śatruvat

Translation

To him who has conquered himself by himself, his own self is the friend of himself, but, to him who has not (conquered) himself, his own self stands in the place of an enemy like the (external) foe.

— Alladi Mahadeva Sastri

Word meanings

bandhuḥ

the relative

ātmā

the self

ātmanaḥ

of the self

tasya

of him

yena

by whom

ātmā

the self

eva

even

ātmanā

by him

jitaḥ

conquered

anātmanaḥ

not (conquered), self, whose, his

tu

indeed

śatrutve

in (for) hostility

varteta

may (would) become

ātmā

the self

eva

even

śatruvat

like an enemy

Śaṅkarācārya's commentary

His self is the friend of himself who is self-controlled, who has brought under control the aggregate of the body and the senses. But in the case of a man who is not self-controlled, his own self does injury to himself, just as any external foe may do injury to him.