There was once a Talmudic scholar who was the son of a very wealthy man, the son-in-law of a very wealthy man, and was himself very wealthy. He dedicated almost all of his time to the study of Torah and would not leave his four corners of his home. One day, in the city where he lived, Krakow, Poland, the Caesar came to visit. Everyone left their homes to greet the king and make the blessing on him.
At that moment, the Talmudic scholar stayed home and did not go out to greet the king because he didn't want to waste his time and stop learning Torah. When the king passed by the Talmudic scholar's home, a stone fell out of his house onto the king's horse, and everybody was in an uproar. How could anybody have the nerve to try to harm the king? Who would do such a thing? The security officers came to the home and found none other than the Talmudic scholar sitting and learning. Of course, the Talmudic scholar denied any wrongdoing. But the king was sure that he was the culprit. Even though the Talmudic scholar claimed that he was innocent, the king decreed that he should be put to death. All the Jews in Krakow could not believe it. They knew that he was a tzaddik (a righteous man) and would never do anything to harm the king. They tried to send letters to the kingdom, and they begged for him to be found innocent, until the king decided to ask the chief rabbi of Krakow if he believed that the Talmudic scholar was innocent. If so, he would let him live.
To everyone's bewilderment, the rabbi of the city kept quiet and didn't say anything about the Talmudic scholar. It was a wonder to everybody: How could he stay silent? The young Talmudic scholar was taken out to be put to death. After he was put to death, the rabbi of the city asked the Chevra Kadisha (burial society) to bring the Talmudic scholar's body to the great synagogue in Krakow. When they brought him to the synagogue, the rabbi went over to the body and said, “I'm commanding you by the Torah to get up and let everybody know why you were put to death, so that nobody will speak about me and complain.”
To everybody's amazement, the dead body got up in front of everybody and said, “I am the neshamah (soul) so and so that threw the first stone on the great and holy prophet Yirmiyahu Hanavi, and therefore I was sent down to this world over ten times in order to correct my neshamah for that sin I did against the Holy Prophet Yirmiyahu. In this gilgul (reincarnation), I have finally fixed my neshamah and I am clean, and the rabbi saw in his wisdom and his prophecy and did not want to find merit in me, so that I could have my neshamah return to its final resting place.” All this was said by the deceased Talmudic scholar. From then on, nobody spoke about the rabbi. They knew that his spirit of holiness made him silent.
From this story, we see how important it is not to do anything against a Talmid Chacham (Talmudic scholar), and not to a prophet, obviously. And certainly not to speak about anybody who is of Torah knowledge.