《资治通鉴·唐纪·唐纪二十八》
之所以又定下减少服丧期的礼节，是为了表明尊卑地位的不同，并以此与戎狄区别开来，世俗的感情肤浅，未能了解圣人制礼的用心，这种定制一经打破，谁还能加以匡正呢！ 
厌降之礼，所以明尊卑、异戎狄也。俗情肤浅，不知圣人之心，一紊其制，谁能正之！ 
The reason for setting up the etiquette of reducing the mourning period is to show the difference in status and to distinguish it from the Rong and Di. The secular feelings are superficial, and they fail to understand the intention of the saints to make the ceremony. Once this custom is broken, who can correct it?