首楞嚴義疏注經 1.88

1.88

前求密義，今宣深奧，隨其所問皆與說示。如《法華》先說《無量義經》以為一乘之本。今此會中亦復如是，必有經目，隱而不言也。

Previously they sought the secret meaning; now he proclaims the profound and unfathomable, preaching and showing to each in accordance with what was asked. Just as in the Lotus Sūtra he first preached the Sūtra of Innumerable Meanings to serve as the root of the One Vehicle. In this assembly now it is also like this; there must have been a title of a sūtra, kept hidden without being stated.