That’s why I said that you can get to know a person’s wisdom by discussion. But only after a long time, not casually; only when attentive, not when inattentive; and only by the wise, not the witless. These are the four things that can be known in four situations.”

Numbered Discourses 4.193 20. The Great Chapter With Bhaddiya

At one time the Buddha was staying near Vesālī, at the Great Wood, in the hall with the peaked roof. Then Bhaddiya the Licchavi went up to the Buddha, bowed, sat down to one side, and said to him:

“Sir, I have heard this: ‘The ascetic Gotama is deceitful. He knows a conversion trick, and uses it to convert the disciples of those of other religions.’ I trust those who say this repeat what the Buddha has said, and do not misrepresent him with an untruth? Is their explanation in line with the teaching? Are there any legitimate grounds for rebuttal and criticism?”

“Please, Bhaddiya, don’t go by oral transmission, don’t go by lineage, don’t go by testament, don’t go by canonical authority, don’t rely on logic, don’t rely on inference, don’t go by reasoned train of thought, don’t go by the acceptance of a view after deliberation, don’t go by the appearance of competence, and don’t think ‘The ascetic is our respected teacher.’ But when you know for yourselves: ‘These things are unskillful, blameworthy, criticized by sensible people, and when you undertake them, they lead to harm and suffering’, then you should give them up.