Bhagavad Gita 6.34

चञ्चलं हि मनः कृष्ण प्रमाथि बलवद्दृढम्।तस्याहं निग्रहं मन्ये वायोरिव सुदुष्करम् ॥६.३४॥

cañcalaṃ hi manaḥ kṛṣṇa pramāthi balavaddṛḍhamtasyāhaṃ nigrahaṃ manye vāyoriva suduṣkaram

The mind is indeed restless, turbulent, strong, and unyielding, O Krishna; I consider it as difficult to control as controlling the wind.

गीता