四分律刪繁補闕行事鈔 1.260

1.260

二明戒場者。律云：以僧中數有四人眾起，乃至二十人眾起，令僧疲極。佛聽結之。不言大小。《善見》云：戒場極小容二十一人，減則不聽。餘如後結。

Second, explaining the precept platform (sīmā-maṇḍala): The Vinaya states that because groups of four people up to groups of twenty people repeatedly stood up in the midst of the saṃgha, causing the saṃgha to be exhausted, the Buddha permitted demarcating it. It does not state its size. The Samantapāsādikā says that the smallest precept platform must accommodate twenty-one people, and if it accommodates less, it is not permitted. The rest is as explained under its demarcation below.