首楞嚴義疏注經 2.224

2.224

一界，初天也。一室，講堂也。借力見寬、自力見狹，寬狹既著，縮斷堪疑，猶豫在懷，故云不知斯義所在。以阿難未證真如，未發真用，佛隨外相對物辨真，既未親證，故難領會。此之疑意，亦約外相以明縮斷，乘前起難以洗物情。

"An entire realm" means the first heaven. "A single room" means the lecture hall. Borrowing [the Buddha's] power, the seeing was broad; using his own power, the seeing is narrow. Since broad and narrow are manifest, shrinking and severing may be suspected; with hesitation in his heart, he thus says: 'I do not know where the meaning in this lies.' Because Ānanda has not yet realized tathatā and has not yet brought forth true functioning, the Buddha, following external appearances, discerns the true in contrast to objects; since he has not personally verified it, it is difficult to grasp. The sense of this doubt also draws on external appearances to clarify shrinking and severing, raising a difficulty based on what preceded in order to wash away clinging to objects.