《左传·昭公·昭公五年》
从郊外慰劳一直到赠送财货，没有违背礼节，为什么不懂得？ 
自郊劳至于赠贿，礼无违者，何故不知？ 
He never deviated from the rules of ritual in offering condolences from the outskirts and in giving presents, so how could he not have a grasp of it?