As it is in the body, so it is in the mind; practice makes it what it is, and most even of those excellencies, what are looked on as natural endowments, will be found, when examined into more narrowly, to be the product of exercise, and to be raised to that pitch, only by repeated actions.
John LockeWhoever uses force without Right ... puts himself into a state of War with those, against whom he uses it, and in that state all former Ties are canceled, all other Rights cease, and every one has a Right to defend himself, and to resist the Aggressor.
John LockeSet the mind to work, and apply the thoughts vigorously to the business, for it holds in the struggles of the mind, as in those of war, that to think we shall conquer is to conquer.
John Locke