《资治通鉴·陈纪·陈纪三》
杨荐知道后，斥责木杆可汗说： 太祖从前和可汗共同敦守友好相处，蠕蠕部落几千人来投降，太祖把他们全部交给可汗的使者，以满足可汗的要求，为什么今天忽然背恩忘义，唯独不有愧于鬼神吗？ 
荐知之，责木杆曰： 太祖昔与可汗共敦邻好，蠕蠕部落数千来降。太祖悉以付可汗使者，以快可汗之意。如何今日遽欲背恩忘义，独不愧鬼神乎？ 
When Yang Jian found out, he rebuked Mugan Khan and said: "In the past, the Great Ancestor and the Khan maintained friendship together. When thousands of people from the Rouran tribe came to surrender, the Great Ancestor handed them all over to the Khan's emissaries in order to satisfy the Khan's request. Why do you suddenly turn against us and become ungrateful today? Are you not ashamed before the gods?"