The ancient Assyrian city of Nineveh, once the most powerful capital of the ancient world, has special importance for anyone familiar with the Bible. It was the setting for the book of Jonah, a place to which God sent the prophet to warn its inhabitants of impending destruction unless they repented of their evil ways.

Today it is known as Mosul, the second-largest city in Iraq. And last week, almost unnoticed amid the horrific stream of news about violence in the Mideast, a fresh casualty of Islamic extremism was the towering structure that contained the tomb of Jonah. Militants of the Islamic State of Iraq and al-Sham who blew up the prophet's tomb either didn't know or didn't care that it was Muhammad himself who, in the Quran, described Jonah as "a righteous preacher of the message of God."

It is remarkable that Jonah achieved significant importance in the religious traditions of all three major monotheistic faiths. His biblical book is short, all of four chapters, totaling 48 sentences. In the Christian Bible, it is found in the section called "The Minor Prophets." In the Jewish version, Jonah is lumped in with 11 others in the work known as "The Twelve."

People walk amid the rubble of the destroyed Mosque of The Prophet Younis, or Jonah, in Mosul, Iraq, on July 24. Associated Press

And yet, of all the prophets chosen to be emphasized by Michelangelo in his magnificent frescoes in the Sistine Chapel, the largest and most imposing figure is Jonah. First-time visitors to the chapel often gasp at the sight: Jonah seems to be actually dangling his legs out of the wall and over the altar, while his shoulders and head seem to be leaning back through the roof of the Sistine into the open sky beyond.

Michelangelo was not alone in singling out Jonah for prominence. Jewish tradition echoes the same choice. Yom Kippur, the Day of Atonement, concludes a 10-day period of penitence that begins with Rosh Hashanah. These 10 days are also known as the Days of Awe, each one bringing closer the moment when, without repentance, there is no longer any escape possible from God's heavenly verdict for every individual. As that moment draws near, Jewish tradition requires a recitation of the four chapters of Jonah, which serve as the concluding biblical message of the day and are read in every synagogue around the world.

To understand the reason for the choice of Jonah by Jews is to grasp what must have motivated Michelangelo as well. The Talmudic rabbis felt that the book of Jonah captures the quintessential message for Yom Kippur because it is a story that reminds us that God judges the whole world—not only Jews but also the people of Nineveh as well as the rest of all mankind.

Jonah was the only Jewish prophet sent to preach to the Gentiles. He emphasized the truth that those who follow God have an obligation to help the wicked turn from their evil ways, and that no one can flee from this obligation without suffering the consequences of divine wrath.

That message is at the heart of the most famous element in Jonah's story: When he was called upon by the Almighty to go to the wicked city of Nineveh and to prophesy to its corrupt inhabitants, Jonah first tried to escape from his calling by boarding a ship going in another direction. But he was pursued by God and ended up being swallowed by a giant fish for three days.

From this we learn that no one can hide from God no matter where he or she goes. And yet we may never give up hope that the wicked, no matter how far gone, can be moved to change their behavior. Repentance is always possible. And, most important, repentance is always accepted by God, even at the very last moment before imminent destruction.

Michelangelo surely identified with Jonah because the artist saw himself as also forced into a mission—leaving Florence to paint at the Vatican—that he wanted at all costs to avoid. Jonah cried and prayed to heaven for the liberation of Nineveh's denizens "out of the depths." Michelangelo, who hoped to steer the church from its hedonistic excesses, identified with the prophet whose task seemed impossible and yet prevailed. For Jonah's message was taken to heart by those who heard him—and he thereby saved the people of Nineveh.

How tragic, then, to note that in modern-day Nineveh Jonah's tomb fell victim to people claiming a commitment to the teachings of Islam, yet it was the Prophet Muhammad who once warned, in the collection of Imam Bukhari, that "One should not say that I am better than Jonah."

The desecration of Jonah's final resting place is a blow not only to his memory but more tragically to his message of universal concern for those of all faiths, the message that still remains the only hope for civilized mankind.

Rabbi Blech, a Talmud professor at Yeshiva University in New York, is the co-author, with Roy Doliner, of "The Sistine Secrets: Michelangelo's Forbidden Messages in the Heart of the Vatican" (HarperCollins, 2008).