Bhagavad Gita 6.35

श्रीभगवानुवाच The Blessed Lord said

असंशयं महाबाहो मनो दुर्निग्रहं चलं।अभ्यासेन तु कौन्तेय वैराग्येण च गृह्यते ॥६.३५॥

asaṃśayaṃ mahābāho mano durnigrahaṃ calaṃabhyāsena tu kaunteya vairāgyeṇa ca gṛhyate

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."

गीता