Chapter 2 · verse 68 · gita.yoga.org

Bhagavad Gita 2.68

तस्माद्यस्य महाबाहो निगृहीतानि सर्वशः। इन्द्रियाणीन्द्रियार्थेभ्यस्तस्य प्रज्ञा प्रतिष्ठिता

Therefore, O mighty-armed Arjuna, his knowledge is steady whose senses are completely restrained from sense objects.