Yōga Sūtra 2.41

सत्त्वशुद्धिसौमनस्यैकाग्र्येन्द्रियजयात्मदर्शनयोग्यत्वानि च।

Through purification, when saatwik quality and cheerful mind set is established, one gains single pointed focus, victory over senses, and the ability to directly perceive the self.