Thus I have heard: One time, the Buddha was staying at Anāthapiṇḍada’s Park in Jeta’s Grove of Śrāvastī.
It was then that the Bhagavān addressed the monks, “If someone were to cease one thing, I’d bear witness that they’ve become a non-returner. What is that one thing? It’s anger. Monks, you should cease anger, then I’ll bear witness that you’ve become non-returners.”
The Buddha then spoke this verse:
“The stain of anger
Makes sentient beings fall to bad destinies.
One should endeavor to abandon anger,
Then they’ll become a non-returner.”
When the monks heard what the Buddha taught, they rejoiced and approved.