The sign of that purity of heart is that one who has acquired it experiences that state of unconsciousness which is similar to that of dreamless slumber. The Yogin who has acquired that state lives like the steady flame of a lamp which burns in a place where the atmosphere is perfectly still.
लक्षणं तु प्रसादस्य यथा स्वप्ने सुखं स्वपेत्। युञ्जनात्मानमात्मनि। निवाते वा यथा दीपो दीप्यमानो न कम्पते॥