《资治通鉴·唐纪·唐纪五十》
大凡军事行动，是要讲究气势的。士气凝聚便旺盛，士气离散便消沉；声势会合便威猛，声势离析便衰弱。
夫兵，以气势为用者也，气聚则盛，散则消；势合则威，析则弱。
A military operation requires a good momentum. When morale is high, the troops will be strong, when morale is low, the troops will be depressed; when strength is united, the troops will be powerful, when strength is separated, the troops will be weak.