Last year, in Haaretz, Anshel Pfeffer began an opinion piece about Tisha B’Av with an apocryphal story about Napoleon Bonaparte. The legendary French leader went for a walk one summer night and heard voices lamenting in a strange language. They may have come from a grand synagogue or a miserable hovel.

Upon asking why the men inside were sitting on the floor and mourning, he was told these were Jews grieving for their destroyed temple in Jerusalem. "How long ago did this happen?" asked Bonaparte. "Eighteen-hundred years" was the answer.

"A nation that can mourn for so long the loss of its land and temple," the emperor is supposed to have said prophetically, "will return one day to their land and see it rebuilt."

This is a moving story about the power of Tisha B’Av to evoke a historical memory for the Jewish people. Pfeffer acknowledges this, and then goes on to argue that the Ninth of Av has “lost any relevance beyond the historical.”

Pfeffer’s argument has been heard before. Many have wondered, after the founding of Israel, if there really is a need for a day of fasting and mourning the destruction of the temples in Jerusalem and the exile of the Jewish people. This claim was strengthened after the Six Day War, when Israel captured the Jordanian-held Jerusalem and the Temple Mount itself.

It’s a good argument, and even has support in our tradition. The prophet Zechariah says that, when the Jewish people return to Israel, the four fast days of mourning will become days of a rejoicing. So why still fast?

Despite this arguably logical line of reasoning, the observance of Tisha B’Av connects the Jewish people to its history, to Israel, and to fellow Jews in a powerful way. As study after study shows the fraying of these relationships, marking Tisha B’Av can reinforce these ties.

Though the Mishna states that five tragedies occurred on Tisha B’Av, the list has grown. In addition to the sin of the spies, the destruction of the temples, the putting down of Bar Kochba’s revolt, and the plowing under of the Temple Mount by the Romans, lists of the calamities that have befallen our people on Tisha B’Av now include the expulsion of the Jews from Spain in 1492, the outbreak of World War I in 1914, and the mass liquidation of Jews in the Warsaw Ghetto in 1942.

Tisha B’Av is a day, like many practices in Judaism, which has taken on additional meaning as the centuries have unfolded to this day. The Masorti movement in Israel has declared Tisha B’Av this year as a day of solidarity with the “tent protest” movement. It is imploring people to remember the lesson of sinat hinam, of senseless hatred, that led to the destruction of the second Temple.

Tisha B’Av provides a framework to address issues that are availing society today.

Tisha B’Av serves not only as a reminder of the tragedies that have befallen us, but also how we made it through as a people. The notion of peoplehood is waning today. Our personalized cultural celebrates the individual over the community, while Judaism teaches the opposite.

This is why the mourning period is canceled out for holidays, we can only pray a full service with a minyan, and most of our prayers are written in the plural. Judaism, which has always been counter-cultural, is even more so today. While on Yom Kippur we fast and atone for ourselves as individuals, on Tisha B’Av we do these things for the community.

Our diversity of opinions in Jewish life does not preclude our unity as a people. We have rarely had strength in numbers, but we have always had strength in purpose. At times it feels like we are losing that today. Tisha B’Av reminds us of the terrible consequences of not working together for the good of all of our people - a lesson both Jews in Israel and abroad could stand to remember.

As we learn in Ta’anit, the section of the Talmud about fasting, “All who mourn for Jerusalem will see her in her joy...” Napoleon was right – we have returned to our land and seen it rebuilt. But that does not mean that Tisha B’Av has lost its meaning. On the contrary, its lessons deeply resonate in the face of the challenges that confront us today in both Israel and the greater Jewish world.

Rabbi Micah Peltz is a conservative rabbi at Temple Beth Sholom in Cherry Hill, New Jersey.