Bhagavad-gītā 6.6
BG 6.6
Open the full passageबन्धुरात्मात्मनस्तस्य येनात्मैवात्मना जितः । अनात्मनस्तु शत्रुत्वे वर्तेतात्मैव शत्रुवत् ॥६॥
Sanskrit
bandhur ātmātmanas tasya yenātmaivātmanā jitaḥ anātmanas tu śatrutve vartetātmaiva śatru-vat
Translation
For him who has conquered the mind, the mind is the best of friends; but for one who has failed to do so, his mind will remain the greatest enemy.