Franz Kafka's quote suggests that when confronted with deep emotional or existential pain, one should maintain inner calm and composure. The imagery of a sword piercing the soul symbolizes profound suffering that can be debilitating if not addressed with equanimity. By staying unyielding and not succumbing to despair, the individual can navigate through their anguish.

Additionally, the idea of becoming "invulnerable" after experiencing such a profound wound implies a transformation through acceptance of pain. Instead of allowing suffering to define them, one can emerge stronger and more resilient, akin to a stone that remains unaffected by external forces. This perspective encourages embracing hardships as a path to personal growth.