A call for prayer from the Pope shouldn't come as a surprise, but this one did.

On his trip through the Holy Land last month — one that energized many Palestinians and angered some Israelis, while avoiding deep offence — Pope Francis invited Israeli and Palestinian presidents Shimon Peres and Mahmoud Abbas to the Vatican to pray with him.

It was one of several unexpected turns, and perhaps the one with the greatest chance to leave a lasting mark. Though no one is expecting miracles, not even Pope Francis himself.

The Pope told reporters travelling with him back to Rome, "This prayer meeting will not be for mediation or to find solutions. We are just meeting up to pray. Then everyone goes home.

"Concrete peace measures have to come from negotiation," he added. "To be honest, I do not feel competent to say we need to do this or that. It would be crazy on my part."

On Sunday, however, Francis will host the two Mideast presidents, joined by a rabbi and a Muslim cleric, as they hold a brief spiritual retreat meant to promote peace.

It is taking place as the latest effort to find common ground between Israelis and Palestinians fizzled just a few weeks ago.

And as animosity is rising over a new Palestinian unity government that Israel won't accept because it has the support of Hamas, the militant Islamic group running Gaza, which Israel accuses of terrorist acts.

To add to the animosity between the two sides, Israel is building more homes in the occupied West Bank, something both the Palestinians and the U.S. say won't help the peace process.

The barrier

The Pope's visit to the West Bank and Israel at the end of May was packed with stops significant and symbolic.

But the most striking image was a brief, unplanned moment at the barrier wall that Israel says it built to prevent terror attacks from the occupied territory.

The pontiff, in white, bowed his head in prayer next to the massive concrete structure covered with graffiti decrying the humiliation Palestinians say they feel.

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In a picture that took off around the world, Pope Francis touches the hulking wall that divides Israel from the Palestinian West Bank, just minutes after begging both sides to end a conflict that he said was no longer acceptable. (Mheisen Amareen / Reuters)

By unexpectedly stopping his motorcade and stepping over to the wall, he seemed to sympathize.

Israeli media reported that officials in Prime Minister Benjamin Netanyahu's office were furious, complaining to the Vatican and then insisting that the Pope make another unscheduled stop — this time at a memorial to Israelis killed in attacks by Palestinians.

The next day, Pope Francis was photographed praying at the Jerusalem memorial, Netanyahu at his side.

It seemed to be part of the familiar zero-sum game of Mideast politics, two sides jockeying for position at the other's expense. And it also seemed that the Pope was playing along.

But Pope Francis had plans of his own, it seems, a third option.

His spiritual approach to the protagonists is one rarely seen in negotiations between Israelis and Palestinians, despite the fact that the two sides are arguing over ownership of some of the holiest places on Earth.

Speaking terms

There are plenty of political observers here who have dismissed the Vatican invitation as nothing more than a publicity stunt, and not only because they reject the power of prayer in a world of hardnosed negotiation.

But also because none of those praying have a great deal of influence in the Middle East.

Israeli President Peres is a largely symbolic figure who has only weeks to go in his term; and despite a personal push for peace during his time in office, he has little control over the country's policies or positions. That's Netanyahu's realm.

Abbas, the president of the Palestinian Authority also hasn't been able to advance his agenda in a huge way, though he has opened the door to a kind of statehood, similar to what the Vatican enjoys, at the UN.

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Israel's President Shimon Peres welcomes the Pope to Israel on May 25. A long-serving Israeli politician and a former prime minister, Peres leaves the largely ceremonial presidency in a few weeks. (REUTERS)

As for the Pope himself, he certainly has moral authority and respect in this region. His warm welcome by regional leaders and religious followers was testament to that.

Still, Christians in general and Catholics in particular don't hold the sway they once had in the Holy Land.

At the same time, there are those in Israel and the West Bank who say the prayer meeting could turn out to be more significant than expected, even if it doesn't lead to a breakthrough or immediate progress in peace talks.

Before the Pope's visit, the very notion that a high-level Israeli statesman could be seen with the head of the Palestinian Authority was almost unthinkable in the current political climate.

Indeed, just before the Pope went to the Middle East, Israeli Justice Minister Tzipi Livni met informally with Abbas in London, in her role as chief peace negotiator for Israel.

That news was immediately met with howls of outrage from the Knesset and calls for her resignation.

Symbolism matters here. So aside from injecting an element of spirituality, images of the two presidents meeting this Sunday could just give people the idea that Israeli and Palestinian leaders are on speaking terms.

Not entirely accurate, but necessary if the peace process is to have a prayer.

Clarifications

  • A previous version of this story said Israel approved new settlements in the West Bank. In fact, Israel is expanding an existing settlement.
    Jun 08, 2014 8:57 AM ET