《魏书·列传·卷四十六》
高祖对诸王、诸贵说： 北都之时，太后严明，我每每被太后所杖罚，左右因此有些是非言语。
高祖谓诸王、诸贵曰： 北京之日，太后严明，吾每得杖，左右因此有是非言论。
Gaozu said to the kings and nobles: When I was in Beidu, the empress dowager was very strict, and I was always punished by the empress dowager. Therefore, there were some right and wrong words on the left and right.