Bona quaecunque aliquis vult in ordine ad bonum finem, bene vult. The things must not only be 'in view of a good end,' they must also be 'good,' that is, permissible, in themselves. See Ethics and Natural Law, p. 32, n. 3. But has not St Thomas said that "on the last end depends all the goodness or wickedness of the will"? Yes, and therefore it is to be further observed that "whoever has placed a good end before him, and regards it steadily with a well-ordered love, never swerving in his affection from the way that reason would have him love, must needs take towards his end those means, and those only, which are in themselves reasonable and just: . . . . thus an end entirely just, holy, and pure, purifies and sanctifies the means, not by investing with a character of justice means in themselves unjust, but by way of elimination, removing unjust means as ineligible" (ib. pp. 36, 37).
Of God and His Creatures: 4.95