《史记·八书·礼书》
所以，完备之极的礼，是内在情感和外在形式全都具备的；次一等的是外在形式胜于内在情感，或者内在情感胜于外在形式，二者具其一；最下等的是内在情感完全归结为天地的本源。
故至备，情文俱尽；其次，情文代胜；其下，复情以归太一。
Therefore, the most perfect form of propriety embraces the feeling within and the expression without; the second best includes the one of these two; and the inferior is that in which the feeling of the heart alone exists, of which Heaven and Earth are the origin.