《六韬·龙韬·立将》
臣怀二心就不能忠心侍奉君主，将帅受君主牵制而疑虑重重就不能专心一志去对付敌人。
二心不可以事君，疑志不可以应敌。
If a subject has second thoughts, he cannot serve the monarch; if a commander is restricted by the monarch and has many doubts, he cannot wholeheartedly tackle the enemy.