《左传·文公·文公六年》
我听说《前志》上有这样的话： 有惠于人或有怨于人，和他的后代无关，这合于忠诚之道。 
吾闻前志有之曰： 敌惠敌怨，不在后嗣 ，忠之道也。
I heard in the “Selected Passages” that whether one has provided favors to someone or has borne a grudge against someone, his descendants are not involved. This conforms to the way of loyalty.