Chapter 6 · verse 35 · gita.yoga.org
Bhagavad Gita 6.35
श्री भगवानुवाच असंशयं महाबाहो मनो दुर्निग्रहं चलं। अभ्यासेन तु कौन्तेय वैराग्येण च गृह्यते
The Blessed Lord said, "Undoubtedly, O mighty-armed Arjuna, the mind is difficult to control and restless; but with practice and dispassion, it can be restrained."