चञ्चलं हि मनः कृष्ण प्रमाथि बलवद्दृढम्। तस्याहं निग्रहं मन्ये वायोरिव सुदुष्करम्।।
The mind verily is restless, turbulent, strong and unyielding, O Krishna: I deem it as difficult to control it as to control the wind.