Verse 48

योऽन्तःशीतलया बुद्ध्या रागद्वेषविमुक्तया ।साक्षिवत्पश्यतीदं हि जीवितं तस्य राजते

In plain words

'He who, with a buddhi cool within and freed of attachment and aversion, looks on this, indeed, as a witness -- life befits him.