At one time Mahāpanthaka was trying to teach Cudapanthaka outside of the vihāra because it was simply too embarrassing to teach him in front of others. They were out in the fields.
Mahāpanthaka: “All things are impermanent; therefore there is no-self. Okay, now you say it.”
Cudapanthaka: “All things are impermanent. Therefore… therefore….”
Mahāpanthaka: “Therefore no-self! No-self!”
Cudapanthaka: “Yes, no-self. No-self because… because…”
Mahāpanthaka: “Because of impermanence! Try again!”
Cudapanthaka: “All things are impermanent. Therefore… therefore….” Even the farmer tilting the field turned around and said, “Therefore there’s no-self.”
Frustrated, Mahapanthaka gave up on Cudapanthaka, and left him. Cudapanthaka was so sad; all he could do was cry, and he wanted to leave Sangha. The Buddha, knowing what had happened, went to Cudapanthaka and said to him, “I will go teach you.” The Buddha didn’t bother teaching him concepts, but merely asked him to clean the vihāra.
Cudapanthaka, sweep the ground. While you do it, say, “I sweep away impurity.”
Now, mind you that it’s pointless to sweep the dust from the ground of a vihāra, a forest temple, since it is built right in the forest! It’s not like the vihāra had cement floors during the Buddha’ time that could be swept clean; it is dirt! So basically the Buddha asked him to sweep the dirt from one end of the vihāra to the other. So Cudapanthaka did that. He swept the dirt back and forth. He swept all day long, saying, “I sweep away impurity… I sweep.” In a way, practice is like moving furniture from one end of the room to another. No matter how we rearrange the pieces, there is absolutely no effect on the room! Yet, moving furniture, making it tidy and neat, does help in recognizing the spaciousness of the room.
One day, it dawned on Cudapanthaka that the ground is just dusty, impure—no matter how he swept. All he’s doing is sweeping dirt from one place to another. The Buddha knew this, and suddenly appeared to him and said, “It is not that the ground is impure, it just seems so because of the dust. It is the same with the impurity of craving, aversion, and delusion that stain your mind.” Suddenly Cudapanthaka had an insight. He realized that just like the ground in the vihāra and the dust that he swept from here to there, his mind is originally clean despite the afflictions. He persisted to meditate on this and very soon realized arhathood.
(Guo Gu's version of the story)
Where did the story of the Arhat Cudapanthaka originate?
different versions:
Book of Serenity:
A monk asked Jiaofan, "Are there differences in the instructions of the old adepts?" Jiaofan said, "The Buddha had an inarticulate, dull monk repeat a broom-sweeping chant; one day he was greatly enlightened and attained great powers of intellect and eloquence. In this you should see the ancient worthies' intention of helping people."