法華義疏 11.153

11.153

上二處為表唯有一乘及法身無二故但放一光，今欲流通此經令二世眾生皆得信持故放一切光也。次分身佛亦現二瑞者，欲顯同一法身皆是應迹故同現二瑞。又眾見多佛現於神力則信敬益深，一佛或可所言不實，十方諸佛何容欺誑？故同現舌相也。

The above two instances were to signify that there is only the ekayāna and that the dharmakāya is non-dual; therefore, he emitted only a single light. Now, wishing to circulate this sūtra and cause living beings of the two time periods all to attain faith and uphold it, he emits all lights. Next, that the emanated buddhas also manifest the two auspicious signs is because he wished to reveal that, having the identical dharmakāya, they are all accommodated traces, and therefore they manifest the two auspicious signs together. Furthermore, when the assembly sees many buddhas manifesting supernatural powers, their faith and reverence deepen all the more. A single buddha might possibly speak what is untrue, but how could the buddhas of the ten directions ever deceive? Therefore they manifest the mark of the tongue together.