Verse 8

प्रहृष्टो न बभूवासौ क्वचिन्न च सुदुःखितः ।प्रकृतेर्व्यवहारत्वात्सदैव सममानसः

In plain words

He was never greatly elated, nor ever greatly sorrowful anywhere, since these are but the workings of prakṛti; he was ever even of mind.