Sanskrit

बन्धुरात्माऽऽत्मनस्तस्य येनात्मैवात्मना जितः। अनात्मनस्तु शत्रुत्वे वर्तेतात्मैव शत्रुवत्।।6.6।।

Summary

To one who has conquered their lower nature with its help, the Self is a friend; but to one who has not done so, it is an enemy.