四分律刪繁補闕行事鈔 2.138

2.138

此十五種自然界，大小如上。若準《四分》，加於勢分。文云：僧伽藍界者，在伽藍邊，中人若用甎石擲所及處，是名界；乃至庫藏界亦如是。諸部並無勢分。《善見》中，無也。彼有擲石之文，別為餘事。彼文云：中人擲石者，不健不羸人盡力擲至落處，不取轉處。諸師評之，一十三步。即以此量，十五自然通著，唯不通法界。必須入界，方乃會衣。《僧祇》云：比丘有緣至他處留宿，彼有比丘及尼，衣有長者，應借受持。無者，俗人有被，應借取，作淨安紐，然後受持。又無衣者，後夜當疾還寺，莫逾城出。到寺門未開者，至門屋下（以門屋梁連界內故。彼律無勢分，以此為自然界，不同《四分》，應知也）。若無者，內手著門孔中，水瀆中；先以物攪，勿令觸毒蟲。又無此孔，應逾牆入，勿令人疑。若不得入，當捨衣。寧無衣，犯小罪，以輕易重故。若準此言，必界內有上三礙，不得外護，必失持衣。故文云：若在餘處宿，明相未出，若至擲石所及處（謂界內無三礙），若手捉衣（謂界內有染情礙），若捨衣（謂界內隔礙等，及界外事）；若不作如上三事，明相出，隨所離衣，犯捨。

These fifteen kinds of natural boundaries are sized as above. If evaluated according to the Dharmaguptaka, a peripheral extension is added. The text states: As for the saṃghārāma boundary, alongside the saṃghārāma, within the reach of a brick or stone thrown by an average person, that is called the boundary; and so on up to the storehouse boundary being the same. None of the other schools have a peripheral extension. In the Samantapāsādikā, there is none. That text does have a passage about throwing a stone, but it is for a different purpose. Its text states: A stone thrown by an average person means a person neither robust nor frail throws with all his strength to where it lands, not taking into account where it rolls. Various masters evaluate it as thirteen paces. Using this measure, it applies generally across the fifteen natural boundaries, but does not apply to formal boundaries (dharma-sīmā). One must enter the boundary in order to meet the robes. The Mahāsāṃghika states: If a bhikṣu goes to another place on some business and stays the night, and there are bhikṣus and bhikṣuṇīs there who have extra robes, he should borrow and sustain them. If there are none, and laypeople have blankets, he should borrow them, make them pure, attach ties, and then sustain them. If there are still no robes, in the latter part of the night he should quickly return to the monastery, not climbing over the city walls to go out. If he arrives at the monastery and the gates are not yet open, he should go under the gatehouse (because the roof beams of the gatehouse connect to the interior of the boundary; that Vinaya has no peripheral extension and takes this as the natural boundary, which should be understood as different from the Dharmaguptaka). If there is no such place, he should put his hand into a gate aperture or into a water conduit; first stirring it with an object so as not to touch venomous insects. If there is no such aperture, he should scale the wall and enter, not letting people suspect him. If he cannot enter, he should relinquish the robes. Better to be without robes and commit a minor transgression, exchanging the heavy for the light. Evaluated according to this statement, if inside the boundary there are the three obstructions mentioned above and one cannot be protected from the outside, one will certainly forfeit the sustained robes. Therefore the text says: If one stays overnight elsewhere, before dawn appears, if one reaches the reach of a thrown stone (meaning there are no three obstructions inside the boundary), or if one grasps the robes with one's hand (meaning there is an obstruction of defiled emotion inside the boundary), or if one relinquishes the robes (meaning there are physical obstructions inside the boundary, or external affairs); if one does not perform these three things, when dawn appears, according to the robes separated from, one commits a forfeiture.