Verse 41

अहं कर्तेति मत्वान्तः कः खेदोल्लासयोः क्रमः ।खेदोल्लासविलासेषु स्वात्मकर्तृतयैतया

In plain words

Having thought within, 'I am the agent' — what sequence of dejection and elation is there? In the very play of dejection and elation, through this very sense of one's own agency,