There is no possibility of thinking of anything at all in the world, or even out of it, which can be regarded as good without qualification, except a good will. Intelligence, wit, judgment, and whatever talents of the mind one might want to name are doubtless in many respects good and desirable, as are such qualities of temperament as courage, resolution, perseverance. But they can also become extremely bad and harmful if the will, which is to make use of these gifts of nature and which in its special constitution is called character, is not good. The same holds with gifts of fortune; power, riches, honor, even health, and that complete well-being and contentment with one's condition which is called happiness make for pride and often herby even arrogance, unless there is a good will to correct their influence on the mind and herewith also to rectify the whole principle of action and make it universally conformable to its end. The sight of a being who is not graced by any touch of a pure and good will but who yet enjoys an uninterrupted prosperity can ever delight a rational and impartial spectator. Thus a good will seems to constitute the indispensable condition of being even worthy of happiness.
Some qualities are even conducive to this good will itself and can facilitate its work. Nevertheless, they have no intrinsic unconditional worth; but they always presuppose, rather, a good will, which restricts the high esteem in which they are otherwise rightly held, and does not permit them to be regarded as absolutely good. Moderation in emotions and passions, self-control, and cam deliberation are not only good in many respects but even seem to constitute part of the intrinsic worth of a person. But they are far from being rightly called good without qualification (however unconditionally they were commended by the ancients). For without the principles of a good will, they can become extremely bad; the coolness of a villain makes him not only much more dangerous but also immediately more abominable on our eyes than he would have been regarded by us without it. (393-4)
Kant, Immanuel. Grounding for the Metaphysics of Morals: On a Supposed Right to Lie because of Philanthropic Concerns. Trans. James W. Ellington. Hackett Publishing 1993.
Works and Days