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 monk Kappa came to visit the Buddha. He bowed his head at the Buddha’s feet and withdrew to stand at one side. he said to the Buddha, “The Bhagavān says ‘a monk’s mind becomes well liberated.’ Bhagavān, how does a monk’s mind become well liberated?”

The Bhagavān told Kappa, “Good! It’s good that you can ask the Tathāgata about one’s mind being well liberated. Good, Kappa! Listen closely! Listen closely, and consider it well. I will explain this for you.”

“Kappa, you should observe and know that whatever forms there are, whether they are past, future, or present, internal or external, crude or fine, beautiful or ugly, or distant or near, they are all impermanent. Having correctly observed that they are impermanent, craving for forms is eliminated. Once craving for forms is eliminated, one’s mind is well liberated.

“In this way, observe whatever feelings … conceptions … volitions … instances of awareness there are, whether they are past, future, or present, internal or external, crude or fine, beautiful or ugly, or distant or near, they are all impermanent. Once one correctly observes that they are impermanent, craving for awareness is eliminated. Once craving for awareness is eliminated, I say one’s mind is well liberated.

“Kappa, when a monk’s mind is well liberated in this way, the Tathāgata says that this is called one’s mind being well liberated. Why is that? Because his craving for desires is stopped. When craving for desires is stopped, the Tathāgata teaches that this is called one’s mind being well liberated.”

When the monk Kappa heard what the Buddha taught, he felt great joy. He then bowed to the Buddha and withdrew. Once he had received the Buddha’s teaching, that monk Kappa went alone to a quiet place, focused on contemplation, and lived earnestly. … Up to … “‘I myself know that I won’t be subject to a later existence.’” His mind was well liberated, and he became an arhat.