A man in Jerusalem held a grand banquet. He had a friend named Kamtza and an enemy named Bar Kamtza. He sent his servant to invite Kamtza. The servant, confused by the similar names, invited Bar Kamtza instead.
Bar Kamtza arrived in good faith. The host looked up from his table, saw his enemy walking in, and ordered him out in front of every guest.
"Now that I am here," Bar Kamtza said, quietly, "do not insult me. I will pay for whatever I eat and drink."
"I want neither your money nor your presence. Leave."
"I will pay the entire expense of your feast. Only do not shame me in front of these guests."
The host refused. Bar Kamtza was thrown out.
As he walked into the street, Bar Kamtza did a dangerous thing. He counted the Rabbis who had been sitting at that table, watching in silence. "Many sages were present," he thought, "and not one rose to defend me. This humiliation must have pleased them."
That private grievance became a public disaster. Bar Kamtza went to the Roman emperor and whispered that the Jews had rebelled. The emperor was skeptical. "How can I know?" Send a sacrifice to their Temple, Bar Kamtza said. See whether they accept it.
The emperor dispatched a perfect calf. On the road, Bar Kamtza secretly inflicted a small blemish — a scratch invisible to Roman eyes but fatal to the priestly inspection. At the Temple, the animal was rejected.
The Rabbis debated whether to sacrifice it anyway, to preserve peace with Rome. They decided not to. Rome took the rejection as proof of rebellion. The Second Temple fell.
Gittin 55b remembers: Jerusalem was destroyed because of the distance between Kamtza and Bar Kamtza — the shame at one dinner table that no one stood up to stop.