* If we examine accurately the notion of respect for persons as it
has been already laid down, we shall perceive that it always rests
on the consciousness of a duty which an example shows us, and that
respect, therefore, can never have any but a moral ground, and that it
is very good and even, in a psychological point of view, very useful
for the knowledge of mankind, that whenever we use this expression
we should attend to this secret and marvellous, yet often recurring,
regard which men in their judgement pay to the moral law.
It is of the greatest importance to attend with the utmost exactness
in all moral judgements to the subjective principle of all maxims,
that all the morality of actions may be placed in the necessity of
acting from duty and from respect for the law, not from love and
inclination for that which the actions are to produce. For men and all
created rational beings moral necessity is constraint, that is
obligation, and every action based on it is to be conceived as a duty,
not as a proceeding previously pleasing, or likely to be pleasing to
us of our own accord. As if indeed we could ever bring it about that
without respect for the law, which implies fear, or at least
apprehension of transgression, we of ourselves, like the independent
Deity, could ever come into possession of holiness of will by the
coincidence of our will with the pure moral law becoming as it were
part of our nature, never to be shaken (in which case the law would
cease to be a command for us, as we could never be tempted to be
untrue to it).
{BOOK_1|CHAPTER_3 ^paragraph 20}
The moral law is in fact for the will of a perfect being a law of
holiness, but for the will of every finite rational being a law of
duty, of moral constraint, and of the determination of its actions
by respect for this law and reverence for its duty. No other
subjective principle must be assumed as a motive, else while the
action might chance to be such as the law prescribes, yet, as does not
proceed from duty, the intention, which is the thing properly in
question in this legislation, is not moral.