¹³ It is a confidence in the promise of the moral law. But this promise is not regarded as one involved in the moral law itself, but rather as one which we import into it, and so import on morally adequate grounds. For a final end cannot be commanded by any law of reason, unless reason, though it be with uncertain voice, also promises its attainability, and at the same time authorizes assurance as to the sole conditions under which our reason can imagine such attainability. The very word fides expresses this; and it must seem suspicious how this expression and this particular idea find a place in moral philosophy, since it was first introduced with Christianity, and its acceptance might perhaps seem only a flattering imitation of the language of the latter. But this is not the only case in which this wonderful religion has in the great simplicity of its statement enriched philosophy with far more definite and purer concepts of morality than morality itself could have previously supplied. But once these concepts are found, they are freely approved by reason, which adopts them as concepts at which it could quite well have arrived itself and which it might and ought to have introduced.