四分律刪繁補闕行事鈔 1.158

1.158

言露地伸手不及者，此言相顯。覆處不須。露地加法，必須相接。說戒羯磨等師，並在僧一尋之內，令伸手相及。所為之人，雖非數限，亦須相內。

In an open space beyond arm's reach: this sign is obvious. In a covered space, it is not required. In the open space, when performing a procedure, they must be contiguous. The master of upoṣadha recitation, the karman master, and others must all be within one fathom of the saṃgha, so that they are within arm's reach. As for the person for whom it is performed, although not within the quorum count, he must also be within reach.