《贞观政要·卷六·论俭约》
贞观元年，太宗对侍臣说： 自古帝王凡是有兴土木的大事，必须以物资人力来衡量利弊。
贞观元年，太宗谓侍臣曰： 自古帝王凡有兴造，必须贵顺物情。
In the first year of Zhenguan, Taizong said to the courtiers: Since ancient times, all emperors who have had major projects of earthworks and construction must use materials and manpower to weigh the pros and cons.