首楞嚴義疏注經 1.107

1.107

當日初分乞食易得，故云即時。鉢多羅，此云應量器，色與體量皆應法度也。無問淨穢，故云次第。順於軌則，故云循乞。乞食十利，如《寶雨經》說。

In the first part of the day, almsfood is easy to obtain, hence it says "at that moment." Pātra is translated here as "vessel of appropriate measure," its color, material, and measure all corresponding to the Dharma's rules. Without inquiring whether pure or impure, hence it says "in turn." Conforming to the proper rules, hence it says "begging in turn." The ten benefits of begging for food are as explained in the Sūtra of Precious Rain (Ratnamegha-sūtra).