法華玄論 9.40

9.40

答：集餘佛者，不得顯釋迦是應迹也。又欲顯二種本迹，以多寶竝坐顯十方諸佛如來同共一法身，又集釋迦分身故顯一佛自有本迹。

Answer: If other buddhas were gathered, one could not reveal that Śākyamuni is a responsive trace. Furthermore, wishing to reveal two kinds of root and trace: by Prabhūtaratna sitting side by side, it reveals that the Tathāgatas, all buddhas of the ten directions, share the same single dharmakāya; and by gathering Śākyamuni's emanations, it reveals that a single buddha inherently possesses his own root and traces.