If even a little restlessness remains in the heart after death, the entire gravestone will shatter into pieces and blow away.

The poet speaks of a passion so volcanic and alive that even the finality of death cannot pacify it. While the grave is usually seen as an eternal resting place weighted down by heavy stone, the poet warns that if even a whisper of his heart's restlessness survives, it will shatter that tombstone to dust. It is a striking and dramatic metaphor for a longing so fierce that not even mortality can contain its power.