bibi sleepFor decades, rejection of Israel—sometimes mixed with outright anti-Semitism—has been a defining theme of Arab politics, uniting bickering countries against a common foe. 

Former Egyptian President Mohammed Morsi, a Muslim Brotherhood leader who was deposed in a 2013 coup, had gone on TV three years earlier to brand Jews as “descendants of apes and pigs.” In 1988, the Palestinian militant group Hamas adopted a covenant that cited the notorious anti-Semitic forgery known as the Protocols of the Elders of Zion as proof of a global Jewish conspiracy.

But attitudes are beginning to change in some parts of the Arab world. Mohammad bin Abdul Karim al-Issa, the secretary-general of the Muslim World League, a Saudi-based global organization that has been accused of spreading extremism, recently pointed to a lesson in coexistence from Islam’s past. “The neighbor of the Prophet [Muhammad] was a Jew, and when that Jew was ill, the Prophet visited him and gave him kind words,” said Mr. al-Issa, who is also a former Saudi minister of justice. “The hard-liners don’t wish to know that.”

This new tone toward Jews—and, to a lesser degree, Israel—is becoming particularly prominent in the Gulf states, led by Saudi Arabia. For these wealthy Sunni monarchies, it is Shiite and Persian Iran that poses the most pressing current threat to their interests. They view the Jewish state—a foe of the regime in Tehran and its regional proxies, including Lebanon’s Hezbollah militia—as their de facto ally.

This unlikely partnership has gathered steam with the rise of Saudi Arabia’s new deputy crown prince, Mohammed bin Salman, the architect of the Yemen war, who wants a more vigorous response to Iran. And it has received new momentum since the election of Donald Trump, the preferred candidate of Israel and the Gulf states. The White House said Thursday that Mr. Trump’s first foreign trip as president will feature stops in both Israel and Saudi Arabia.

“We have the same enemy, the same threat,” Saudi Maj. Gen. Ahmed Asiri, now the kingdom’s deputy intelligence chief, said in February. “And we are both close allies of the Americans.”

Pressure from the Gulf—particularly from Hamas’s longtime backer Qatar—played a key role in the Palestinian group’s decision Monday to remove slurs against Jews from its revised charter. Israel scoffed at the changes, noting that Hamas retained its goal of “liberating” all of historic Palestine—which would mean eradicating the Jewish state.

Still, some Israeli officials have praised the Gulf monarchies’ shift on Hamas. “Most of [Hamas’s] support came from Saudi Arabia and the Gulf in the past,” said Ayoob Kara, a lawmaker from Prime Minister Benjamin Netanyahu’s Likud Party and the only Arab minister in Israel’s cabinet. “Now the Saudi Arabian coalition understands more and more that Hamas is an extremist organization and that extremism and terror are also against them, not just against Israel.”

The Gulf states also shape opinion across the Arab world: Most of the influential TV news channels and pan-Arab newspapers are owned by Saudis, Qatari or Emiratis. “On TV, we no longer hear the usual words ‘Israeli aggression.’ Now, it’s mostly about the ‘Persian aggression,’ ” said Ahmad al-Ibrahim, a Saudi businessman and political analyst.

Sympathy for the Palestinian cause and rejection of Israel still run deep in the region, particularly in countries far from Iran that don’t view it as much of a threat. Such feelings are widespread among the people of the Gulf states too, so most of the recent cooperation with Israel—focusing on intelligence and security matters—has occurred in secret.

But some small steps have been public. An unofficial Saudi delegation, led by a retired general, visited Jerusalem last year and met with Israeli officials. The United Arab Emirates has permitted a small Israeli mission to the U.N.’s renewable-energy agency, based in Abu Dhabi, and Emirati officials are weighing whether to allow low-key Israeli participation in the 2020 Dubai World Expo.

Such an erosion of Arab hostility to Israel rattles many Palestinians. “I am in favor of normalizing between Israel and all Arab countries—one minute after an independent Palestinian state is established,” said Ayman Odeh, the head of the Arab bloc in Israel’s parliament. “Agreements between Israel and Arab countries before the Palestinian issue is solved will weaken the Palestinian cause.”

Many in the Gulf shrug at such complaints. “Saudi Arabia has always wanted to support the Palestinian cause. It negotiated on their behalf, it spent a lot of money on their behalf,” said Mr. Ibrahim. “But unfortunately, the Palestinian leaders do not want to get along and are not working for their own people. You cannot just say no to everything.”