On what refusal to forgive protects
“The weak can never forgive. Forgiveness is the attribute of the strong.”
Said flatly, this can sound like a taunt. It reads better as a description of what holding a grievance is for: it keeps a position that would otherwise have to be given up, and positions are what people hold when they have little else.
Strength here is not moral superiority. It is having enough that letting one thing go does not cost the whole standing. That is worth remembering before applying the line to anyone but yourself.