All over the West since the Oct. 7 Hamas massacre of 1,400 Israelis, Muslim demonstrators have been calling for a new genocide of the Jews, right under the noses of authorities, and yet those authorities have taken no notice. One problem is that the threat was in Arabic, and authorities in Europe and North America don’t generally speak Arabic yet. Another problem is that even when it is translated into English, the threat doesn’t appear at first glance to be as bloodcurdling as it actually is. But as the demonstrations grow more heated, it becomes increasingly unwise for authorities to continue to ignore these clear threats of violence.

The threat comes in the form of a chant, “Khaybar, khaybar, ya yahud, jaish Muhammad sa yaoud,” a rhythmic phrase that lends itself well to public protests and fits right in with the bleating of “Free, Free Palestine!” and all the rest. Most recently, anti-Israel protesters chanted it last Saturday in London, but it has been heard at pro-Hamas demonstrations all over the country. I remember being shocked to hear it from anti-Israel protesters in New York City back in 2014, but by now it has become commonplace at such protests.

The chant means “Khaybar, Khaybar, O Jews, the army of Muhammad shall return.” There is an unmistakable hint of violence in the warning that an army will be along, but one can hear Islamic apologists and their Leftist allies now explaining that the “army of Muhammad,” the prophet of Islam, simply stands for all that is good and true, making the chant nothing more than a declaration that the righteous will prevail over the sinful. Unfortunately, however, the army of Muhammad was more than just a band of spiritual warriors.

According to Islamic tradition, Muhammad, in fact, led actual armies into battle, and on more than one occasion fought aggressive wars. “The History of Jihad From Muhammad to ISIS” details how early Islamic sources say that Muhammad led a Muslim force against the Khaybar oasis, a place that was inhabited by Jews. Most of them were not natives of Khaybar; they had actually been exiled by the same Muhammad from the Arabian city of Medina for not converting to Islam and for supposedly conspiring against him, although the Islamic sources place his demand that they convert before any such alleged conspiracies.

After exiling the Jews of Arabia to Khaybar, Muhammad took his army to that oasis and attacked them there. In doing so, he was not responding to any provocation. After the exiles and the violence that accompanied them, the Jews constituted no threat to him. But Muhammad had just concluded a treaty that was disadvantageous to the Muslims, and to quiet his disgruntled followers had promised them massive spoils in the near future. Khaybar offered that.

The traditions depict one of the Muslims recounting what happened: “When the apostle raided a people he waited until the morning. If he heard a call to prayer he held back; if he did not hear it he attacked.” That is, if there were Muslims in a town, Muhammad wouldn’t invade, but if there weren’t, all bets were off.

The Muslim continued: “We met the workers of Khaybar coming out in the morning with their spades and baskets. When they saw the apostle and the army they cried, ‘Muhammad with his force,’ and turned tail and fled. The apostle said, ‘Allahu akbar! Khaybar is destroyed. When we arrive in a people’s square it is a bad morning for those who have been warned.’”

Once they entered Khaybar, the Muslims immediately set out to locate the inhabitants’ wealth. A Jewish leader of Khaybar, Kinana bin al-Rabi, was brought before Muhammad; Kinana was supposed to have been entrusted with the treasure of one of the Jewish tribes of Arabia, the Banu Nadir. Kinana denied knowing where this treasure was, but Muhammad pressed him: “Do you know that if we find you have it, I shall kill you?” Kinana said yes, that he did know that.

Treasure was found, but the Muslims believed there was more to be had. Muhammad gave orders concerning Kinana: “Torture him until you extract what he has.” One of the Muslims built a fire on Kinana’s chest, but Kinana would not give up his secret. When he was at the point of death, one of the Muslims beheaded him. Kinana’s wife Safiyya bint Huyayy was taken as a war prize; Muhammad claimed her for himself and hastily arranged a “wedding” ceremony that night. He halted the Muslims’ caravan out of Khaybar later that night in order to “consummate” the marriage.

Thus when modern-day Muslims invoke Khaybar, they are recalling an aggressive surprise raid by Muhammad that resulted in the final eradication of the once considerable Jewish presence in Arabia. To jihadists, Khaybar means the destruction of the Jews and the seizure of their property by the Muslims. The fact that modern pro-Palestine demonstrators want exactly that is all too clear.