BERLIN - Six years ago, shortly after Daniel Alter became one of the first Jews to be made a rabbi in Germany after the Holocaust, he said that he thought for a long time about how to explain to his daughter why there were relatively few Jews in Germany. He told DieWelt: "To tell you honestly, I don’t know how to tell her."

Six years ago his daughter was a baby. Last Tuesday evening in the Berlin neighborhood of Schöneberg, she was with her kippa-wearing father when four youths – presumed to be of Arab origin -- asked him: "Are you a Jew?" and then insulted and physically assaulted him when he said yes.

Then, one of the attackers turned to Alter’s daughter, now seven years old: "I’m going to kill you!" Alter suffered a broken cheekbone and had to be operated last Thursday.

Alter told Die Welt that the incident would not change his commitment to interreligious dialogue. "My foundations are not shaken," he said. "Many people have contacted me to commiserate, wish me a swift recovery and say that they condemn what happened to me."

Alter said that he had been verbally molested frequently before Tuesday’s incident but hadn’t wanted to admit to himself just how aggressive these incidents were.

The Israeli Foreign Ministry condemned the attack as a "brutal act of racism." In Jerusalem, a spokesperson said that Israel hoped that German authorities would bring the attackers to justice.

One result of the attack is that the police have increased protection of Abraham Geiger College in Potsdam, a rabbinic seminary. Students have been advised not to wear a kippa in the street, rector Walter Homolka told Die Welt. "Until now I’ve been under the illusion that it should be possible wherever and whenever, anywhere in Berlin, to show that one adheres to the Jewish faith."

During his sermon on Saturday, Rabbi Yitzhak Ehrenberg referred to Homolka's warning. "That is not good advice," he told his congregants in Berlin. He said he advises men to decide whether or not they wish to wear a kippa, and if so whether they want to do so openly or remain “invisible.”

As regards wearing the kippa, "the Talmud says one should avoid dangerous places… But Berlin is not a dangerous place. We’re not afraid and we will not stop covering our heads. Shabbat Shalom! A peaceful Sabbath!"

A kippa "flash mob"

Saturday afternoon, on the corner of Kurfürstendamm Avenue and Fasanen Street in Berlin: Sarah Nurit, 35, who works in a day-care center and is single mom to three boys ("all circumsized!"), has called for a kippa flash mob on Facebook. She boasted that: "160 signed up. I’ll be happy if even only 40 show up."

At 2 p.m. Sarah gives the signal: "We’ll start now. I wish you a peaceful Sabbath!" And some 100 Berliners, Jews and non-Jews alike, set off on a walk through downtown, accompanied by a handful of policemen and about a dozen journalists. German jazz musician Max Doehlemann wears an oversize white kippa. David, a young Berliner, has dressed his bulldog Chico in an Israeli army shirt. And Rabbi Tuvia Ben-Chorin, who heads a reform Jewish community in Berlin, is using the occasion to tell jokes.

A previous incident in 2010 in Hannover -- when Muslim children threw gravel at an Israeli dance group performing during a street festival -- made national headlines in Germany. Where does this hatred come from? Islam experts point to satellite TV, which increasingly makes it possible for Arab programs to be viewed in Europe.

Muslim youths, sitting in their living rooms in Germany, can watch programs like the Iranian series that is set in the Gaza strip and shows Israel trafficking in the organs of Palestinian children. "You Jew" has now become a standard insult in German schoolyards.

Daniel Alter used to hope that his ordination was a symbol of the normalization of Jewish life in Germany. Yet he often encountered awkwardness instead, and recalls when some people asked if he were a Jew "many would sort of whisper the word ‘Jew’ as if it were some sort of four-letter term.”

Alter got part of his education in Jerusalem where he says he was "surrounded by people who were like me.” He says that because back in Germany he was often stared at for wearing a kippa, he took to wearing a cap or hat over it. He later stopped doing that. And no, in fact, he was not wearing anything over the kippa when he was assaulted.