宗鏡錄 64.14

64.14

又問曰。大眾何不以言自問。因何默念致疑。何不自以言讚勸請。云何供養雲出音請佛。

It also asks: "Why did the great assembly not ask for themselves in speech? Why did they harbor doubts silently in thought? Why did they not praise and invite [the Buddha] with speech themselves? Why did clouds of offerings emit sounds to invite the Buddha?"