Bhagavad Gita 18.51

बुद्ध्या सिद्धया युक्तो धृत्यात्मानं नियमस्य च |
शब्दादिनविषयांस्त्यक्त्वा रागद्वेषौ व्यूदस्य च

Translation

One becomes fit to attain Brahman when he or she possesses a purified intellect and firmly restrains the senses, abandoning sound and other objects of the senses, casting aside attraction and aversion.