《旧唐书·本纪·卷十四》
在这之前，快到举行祭祀大礼的前夕，天气一连阴暗了十二天，宰臣请求改日举行，宪宗说： 到郊外祭祀，事情重大，斋戒准备的时间是有礼仪规定的，不能突然更改。 
先是，将及大礼，阴晦浃辰，宰臣请改日，上曰： 郊庙事重，斋戒有日，不可遽更。 
Before this, the weather had been cloudy for twelve days in a row. On the eve of the sacrifice, the prime minister asked to change the date. Emperor Xianzong said: "Sacrificing in the suburbs is a major event. The time for fasting and preparation is prescribed by rituals. It cannot be changed suddenly."