The quote highlights the destructive nature of holding onto anger and hatred. The idea is that when we cling to negative emotions, it ultimately harms us more than the person we are upset with. This inner turmoil acts like poison, consuming our well-being and peace of mind.
Mitch Albom suggests that rather than being weapons against others, feelings of hatred and resentment act like a "curved blade," inflicting pain on ourselves. The message encourages letting go of such emotions to avoid self-inflicted damage and to find healing and forgiveness.