We can judge the heart of a man by his treatment of animals.
— Immanuel Kant

It is a wise man who said that there is no greater inequality than the equal treatment of unequals.
Felix Frankfurter treatment quote

Equality consists in the same treatment of similar persons.
— Aristotle

In matters of truth and justice, there is no difference between large and small problems, for issues concerning the treatment of people are all the same.
— Albert Einstein

It is in the treatment of trifles that a person shows what they are.
— Arthur Schopenhauer