Caesar once said to Rabbi Tanchum, "Come, let us become one people."
The rabbi answered calmly. "Very well. But we are circumcised, and we cannot simply become as you are. If, however, you agree to be circumcised yourselves, then we would be alike in that regard, and we could be one people."
The emperor paused and then admitted, "You have answered reasonably. But Roman law decrees that anyone who silences his ruler in argument shall be cast to the lions."
At a word, Rabbi Tanchum was flung into the lions' den. The lions, the tradition reports, would not touch him. A heretic watching the scene scoffed that the beasts simply were not hungry. To test the claim, he was thrown in next, and the lions devoured him at once (Sanhedrin 39a).
The emperor sought a political merger. The rabbi answered with the Torah's own boundary mark, and Heaven answered with the lions.