6:5  

उद्धरेदात्मनात्मानं नात्मानमवसादयेत् ।
आत्मैव ह्यात्मनो बन्धुरात्मैव रिपुरात्मनः ॥६- ५॥

uddharedaatmanaatmaanaM naatmaanamawasaadayet ।

aatmaiwa hyaatmano bandhuraatmaiwa ripuraatmanaH ॥६- ५॥

Source: Automatic ITRANS Transliteration

Raise the self by the self. Let not the self decline.
The self is itself the friend of the self. The self is itself the enemy of the self.

Source: Milind S. Pandit

One must elevate, not degrade, oneself by one's own mindxe "mind". The mind alone is one's friend as well as one's enemy.

Source: The Bhagavad-Gita: The Sacred Song

A man must elevate himself by his own mind, not degrade himself. The mind is the friend of the conditioned soul, and his enemy as well.

Source: Bhagavad Gita As It Is