Chapter 6 · verse 5 · gita.yoga.org

Bhagavad Gita 6.5

उद्धरेदात्मनाऽऽत्मानं नात्मानमवसादयेत्। आत्मैव ह्यात्मनो बन्धुरात्मैव रिपुरात्मनः

One should raise oneself by one's own self alone; let not one lower oneself; for the self alone is one's own friend, and the self alone is one's own enemy.