四分律刪繁補闕行事鈔 3.447

3.447

四獨戒。獨度河四緣：一是河水。《四分》云：獨不能度，不云深廣。今準道行之戒，但使褰衣度水，異陸行威儀，皆犯；大界內河亦犯。有橋者，如常開之。二者獨度。前尼疾疾入水，偷蘭；雙脚上岸，僧殘。後尼獨入水，犯蘭；上岸得前尼為伴，不犯。若乘車船度，皆不犯。律云：彼尼當求一尼共度，應入水隨深淺褰衣，至彼岸漸下衣已，然後一時上岸；若不待後伴，偷蘭。三無緣。除命梵等難，伴命終也。四獨度河，犯。謂後伴隔河，便犯，無相援故。

The four precepts on being alone. Crossing a river alone has four conditions: first, it is river water. The Dharmaguptaka Vinaya says: "Alone, she cannot cross"; it does not specify depth or breadth. Now, basing on the precept on walking on a road, as long as she hitches up her robes to cross the water, departing from the īryāpatha of walking on land, all constitute an offense; a river within a large sīmā also constitutes an offense. Where there is a bridge, it is permitted as usual. Second, crossing alone. If the preceding nun quickly enters the water, it is a thullaccaya; when both feet are on the bank, it is a saṃghāvaśeṣa. If the succeeding nun enters the water alone, she commits a thullaccaya; when she reaches the bank and gains the preceding nun as a companion, there is no offense. If crossing by riding a carriage or boat, none commit an offense. The Vinaya says: That nun must seek a nun to cross together; entering the water, she should hitch up her robes according to the depth, and having reached the other bank and gradually lowered her robes, then ascend the bank together at the same time; if she does not wait for the companion behind, it is a thullaccaya. Third, having no justifying circumstances, except dangers to life or pure conduct, or the death of a companion. Fourth, crossing the river alone, she commits [an offense]; that is, when the companion behind is separated across the river, she immediately commits it, because there is no mutual assistance.