大比丘三千威儀 1.25

1.25

復有四事應行：一者舍屋敗、二者無檀越、三者饒蚊虻毒虫、四者國君嫉妬道。

There are also four circumstances under which one should depart: first, the dwellings are dilapidated; second, there are no dānapatis; third, there are abundant mosquitoes, gadflies, and venomous insects; fourth, the ruler of the land is hostile to the Way.