出三藏記集 1.27

1.27

又十誦律序云。迦葉言。我先從波婆城向拘尸城。道中聞佛涅槃。有愚癡比丘言。我今得自在。所欲便作。不欲便止。又有比丘。非法說法。法說非法。以此因緣應集法藏即羯磨。五百羅漢唯阿難在學地。共住王舍城安居。先令優波離出律藏。一一事竟。即問阿若憍陳如。次問長老均陀及十力迦葉等五百羅漢。乃至最下阿難言如優波離所說不。皆答我亦如是聞是事是法。爾時迦葉僧中唱言。大德僧聽。初事集竟。是法是佛教。無有比丘言非法非佛教。僧忍默然故是事如是持。乃至集律藏一切竟。後方命阿難出修多羅藏及阿毘曇藏。阿難方云如是我聞。一時五百羅漢皆下地胡跪涕零而言。我從佛所面聞見法。而已言我聞。迦葉語阿難。從今三藏初皆稱如是我聞。故復兩存。

The preface to the Daśādhyāya-vinaya also says: Kāśyapa said, "Previously, when I was heading from the city of Pāvā toward the city of Kuśinagara, I heard on the road of the Buddha's nirvāṇa. An ignorant monk said, 'I am now master of myself: what I wish to do, I will do; what I do not wish to do, I will refrain from doing.' Furthermore, there were monks who spoke of non-Dharma as Dharma, and of Dharma as non-Dharma. For this reason, the Dharma-piṭaka should be compiled." Thereupon a karman was performed. Among the five hundred arhats, only Ānanda remained at the stage of a trainee (śaikṣa). They resided together for the summer retreat in Rājagṛha. First, they had Upāli bring forth the Vinaya-piṭaka. When each single matter was concluded, he asked Ājñātakauṇḍinya, and next asked the elder Cunda, Daśabalakāśyapa, and the rest of the five hundred arhats, down to the lowest, Ānanda, saying, "Is it as Upāli has said or not?" All replied, "I too heard this matter and this Dharma to be so." At that time Kāśyapa made an announcement amidst the Saṅgha, saying, "Let the venerable Saṅgha listen: The compilation of the first matter is complete. This is the Dharma; this is the teaching of the Buddha. No monk has said that it is non-Dharma or not the Buddha's teaching. Because the Saṅgha has silently approved, this matter shall be upheld thus." So it proceeded until the entire Vinaya-piṭaka was compiled. Only thereafter did he order Ānanda to bring forth the Sūtra-piṭaka and the Abhidharma-piṭaka. When Ānanda at last said, "Thus have I heard: At one time...," the five hundred arhats all knelt down on the ground in the barbarian posture, and with falling tears said, "We heard and saw the Dharma face-to-face from the Buddha, yet he only says 'I have heard.'" Kāśyapa said to Ānanda, "From now on, the beginning of [all texts of] the three piṭakas shall uniformly say 'Thus have I heard.'" Therefore, both [traditions] are preserved.