More "Who Said This?"
Be no mans lackey. Do not let others tread with impunity on your rights. ... Do not be a parasite or a flatterer or (what really differs from these only in degree) a beggar. ... Bowing or scraping before a man seems in any case to be unworthy of a man. ... Kneeling down or prostrating oneself on the ground, even to show your veneration for heavenly objects, is contrary to the dignity of humanity .... One who makes himself a worm cannot complain afterward if people step on him. ...
Self-esteem is a duty of man to himself.
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Immanuel Kant, in The Metaphysics of Morals.