Verse 16

फलसंधीनि कर्माणि नानाचारमयानि च ।सुखदुःखावपूर्णानि तानि वक्तुं न शक्नुमः

In plain words

Their deeds, tied fast to their fruits, woven of every kind of custom, brimful of pleasure and of pain — these we are simply unable to put into words.