《礼记·檀弓上》
子贡说： 以前夫子哀悼颜渊，其悲痛如同丧子一样，但不穿任何丧服。哀悼子路时也是这样。让我们悼念夫子，就像悼念父亲一样，但也不穿任何丧服。 
孔子之丧，公西赤为志焉：饰棺、墙，置翣设披，周也；设崇，殷也；绸练设旐，夏也。
Zigong said: In the past, the Master mourned Yan Yuan with the same grief as if he had lost his own son, but he did not wear any mourning clothes. It was the same when he mourned Zigong. Let us mourn the Master as if he were our father, but we will not wear mourning clothes either.