Hostile armies may face each other for years, striving for the victory which is decided in a single day. This being so, to remain in ignorance of the enemy's condition simply because one grudges the outlay of a hundred ounces of silver in honors and emoluments, is the height of inhumanity.

Sun Tzu's The Art of War: Bilingual Edition Complete Chinese and English Text (ed. Tuttle Publishing, 2012) - ISBN: 9781462905126