298. The naked ascetic Kassapa said to the Lord: “Reverend Gotama, it is hard to be a true monk, it is hard to be a true brahman.”
The Lord said: “That is what the world says Kassapa. But if a naked ascetic was to practice all kinds of self-mortification, and if this was the measure of difficulty, then it would not be correct to say that it is hard to be a true ascetic or a true brahman. Because anyone, a householder, his son, even a slave girl who draws water, could go naked and mortify themselves. But there is another type of asceticism about which it is true to say that it is hard to be a true ascetic, a true brahman. When a monk develops a mind free from hatred or ill-will, full of love, and by the destruction of the defilements, dwells with a mind freed through insight, then that monk is a true ascetic, a true brahman.”
D.I,168 (DN 8)