There is great ability in knowing how to conceal one's ability.

Isaac De Benserade (1612-1691): Maxim 245.

  All lovers swear more performance than they are able, and yet reserve an ability that they never perform; vowing more than the perfection of ten, and discharging less than the tenth part of one.

William Shakespeare (1564-1616): Troilus and Cressida. Act iii. Sc. 2.

  "War," says Machiavel, "ought to be the only study of a prince;" and by a prince he means every sort of state, however constituted. "He ought," says this great political doctor, "to consider peace only as a breathing-time, which gives him leisure to contrive, and furnishes ability to execute military plans." A meditation on the conduct of political societies made old Hobbes imagine that war was the state of nature.

Edmund Burke (1729-1797): A Vindication of Natural Society. Vol. i. p. 15.

  Nothing has such power to broaden the mind as the ability to investigate systematically and truly all that comes under thy observation in life.

Marcus Aurelius Antoninus (121-180 a d): Meditations. iii. 11.