《汉书·纪·宣帝纪》
从现在起，凡有祖父母、父母丧事的可以免去徭役，使能收殓送终，尽人子之道。 
自今，诸有大父母、父母丧者勿徭事，使得收敛送终，尽其子道。 
From now on, all those who have the misfortune of their grandparents or parents can be exempted from corvée labor, so that they can collect the body and see it off, doing the duty of a son.