分別功德論 4.9

4.9

優留毘迦葉所以稱第一者，乃宿世以來弟兄三人常有千弟子相隨，今遇釋迦文佛世，佛以十八變度迦葉千人，佛眾得成，四事供養猶此而興。以是言之，優留毘迦葉能將護聖眾供養第一也。

The reason why Uruvilvā-Kāśyapa is declared foremost is that since past lives, the three brothers always had a thousand disciples following them. Now encountering the era of Śākyamuni Buddha, the Buddha used eighteen transformations to deliver the thousand men under Kāśyapa; the Buddha's assembly was thereby established, and the offerings of the four requisites arose from this. By this account, Uruvilvā-Kāśyapa was foremost in being able to protect the noble assembly and provide offerings.