三彌勒經疏 1.176

1.176

經曰「爾時彌勒」以下，第二釋疑。疑云：初會眾皆得聲聞果。既爾，彌勒唯說聲聞乘教。是故顯三乘教說也。

From the sūtra saying "At that time, Maitreya..." onward is the second part, resolving doubts. The doubt is: The assembly of the first gathering all attain the fruits of the śrāvaka. If so, Maitreya would only be teaching the doctrine of the Śrāvakayāna. Therefore, it reveals the teaching of the three vehicles.