From Immanuel Kant, The Metaphysics of Morals (1797)
In the system of nature, man (homo phaenomenon, animal rationale) is a
being of slight importance and shares with the rest of the animals, as
offspring of the earth, an ordinary value (pretium vulgare). Although
man has, in his understanding, something more than they and can set
himself ends, even this gives him only an extrinsic value for his usefulness
(pretium usus); that is to say, it gives one man a higher value than
another, that is, a price as of a commodity in exchange with these
animals as things, though he still has a lower value than the universal
medium of exchange, money, the value of which can therefore be
called preeminent (pretium eminens).
But man regarded as a person, that is, as the subject of a morally
practical reason, is exalted above any price; for as a person (homo noumenon) he is not to be valued merely as a means to the ends of
others or even to his own ends, but as an end in himself, that is, he
possesses a dignity (an absolute inner worth) by which he exacts respect
for himself from all other rational beings in the world. He can measure
himself with every other being of this kind and value himself on
a footing of equality with them.
Humanity in his person is the object of the respect which he can demand from every other man, but which he must also not forfeit.
Hence he can and should value himself by a low as well as by a high
standard, depending on whether he views himself as a sensible being
(in terms of his animal nature) or as an intelligible being (in terms of
his moral predisposition). Since he must regard himself not only as a
person generally but also as a man, that is, as a person who has duties
his own reason lays upon him, his insignificance as a human animal may
not infringe upon his consciousness of his dignity as a rational man,
and he should not disavow the moral self-esteem of such a being, that
is, he should pursue his end, which is in itself a duty, not abjectly,
not in a servile spirit (animo servili) as if he were seeking a favor, not
disavowing his dignity, but always with consciousness of his sublime moral predisposition (which is already contained in the concept of virtue). And this self-esteem is a duty of man to himself.
[...]
§12
Be no man's lackey. Do not let others tread with impunity on your rights. [...] Kneeling down or prostrating oneself on the ground, even to show your veneration for heavenly objects, is contrary to the dignity of humanity [...] for you then humble yourself, not before an ideal presented to you by your own reason, but by an idol of your own making.
Immanuel Kant, The Metaphysics of Morals, 1797
[...]
§12
Be no man's lackey. Do not let others tread with impunity on your rights. [...] Kneeling down or prostrating oneself on the ground, even to show your veneration for heavenly objects, is contrary to the dignity of humanity [...] for you then humble yourself, not before an ideal presented to you by your own reason, but by an idol of your own making.
Immanuel Kant, The Metaphysics of Morals, 1797