《晋书·帝纪·第三章》
又顾虑皇孙非贾后所生，终将发生危难，遂与心腹图谋后事，出谋划策者纷然杂出，长久未决，终于用王佑之谋，派遣太子亲弟秦王司马柬都督关中，楚王司马玮、淮南王司马允镇守要害，以加强帝室。
复虑非贾后所生，终致危败，遂与腹心共图后事。说者纷然，久而不定，竟用王佑之谋，遣太子母弟秦王柬都督关中，楚王玮、淮南王允并镇守要害，以强帝室。
He also worried that the emperor's grandson was not born to Empress Jia, and that a disaster would eventually occur, so he conspired with his confidants to plan for the future. Those who made suggestions came up with one after another, but they were not decided for a long time. Finally, Wang You's plan was used to send the crown prince's younger brother, King Qin Sima Jian, to be the governor of Guanzhong, and King Chu Sima Wei and King Huainan Sima Yun to guard the key points to strengthen the imperial family.