The Speech About Wandering Mendicants
This is what I heard. The Buddha was once traveling along the path between Rājagaha and Nālandā, accompanied by about five hundred monks. Suppiya, the wandering mendicant, and his disciple, the young Brahmadatta, were traveling along the same path. Suppiya was criticizing the Buddha, the Dhamma, and the Sangha while his pupil applauded them. In this way, teacher and pupil, holding opinions in direct contradiction to one another, were following, step by step, after the Buddha and the company of monks.
The Buddha, along with the company of monks, entered the Ambalaṭṭhika rest-house to pass the night. Suppiya and his pupil did the same; and they continued their conversation.
Early the next morning, as they awoke, several monks gathered in the pavilion. They conversed as they sat. "How remarkable is this, monks; and how strange is it that the Blessed One—the one who knows and sees, the Arahat, the awakened Buddha—has understood the habits of men with such perfect insight! Watch as Suppiya criticizes the Buddha, the Dhamma, and the Sangha while his own pupil applauds them. In this way, teacher and pupil follow step by step, after the Buddha and the company of monks, holding opinions in direct contradiction to one another."
The Buddha, realizing what the topic of conversation was, made his way to the pavilion and took his seat on the mat spread out for him. After he sat, he said: "What was the conversation you were engaged in, monks? What was the topic of your conversation?"
The monks informed the Buddha of what had transpired and, upon hearing what they said, the Buddha replied:
"Monks, you should not bear resentment, or suffer irritation, or develop enmity against those who criticize me, the Dhamma, or the Sangha. Anger and ill-will stand in the way of self-conquest. If you were to become angry and irritated when others speak against us, would you be able to decide whether their statements hold any merit?"
"Certainly not, Lord."
"You should, instead, point out what is wrong with their criticism. Say: 'For such-and-such reason that is not true, that is not so, you will not find that among or in us.'
Likewise, you should not swell with pleasure, or satisfaction, or elation when outsiders speak well of me, the Dhamma, or the Sangha. Indeed, that too would stand in the way of your self-conquest. You should, instead, acknowledge what is true. Say: 'For such-and-such reason that is true, that is so, you will find that among and in us.'"
Gautama Buddha, Itivuttaka Sutta No. 98