The Art of War by active 6th century B.C. Sunzi

11. Now the general is the bulwark of the State: if the bulwark is

complete at all points; the State will be strong; if the bulwark is defective, the State will be weak. [As Li Ch’uan tersely puts it: "Gap indicates deficiency; if the general’s ability is not perfect (i.e. if he is not thoroughly versed in his profession), his army will lack strength."]