It was a stunning moment, unexpected even by Vatican spokesman Fr. Frederico Lombardi. The pope extended his invitation to the two heads of state at the end of Sunday Mass in Manger Square, Bethlehem.
Lombardi described the invitation as "an initiative of the pope."
" All of us – especially those placed at the service of their respective peoples – have the duty to become instruments and artisans of peace, especially by our prayers," said Pope Francis as he asked Abbas and Perez to join him "in heartfelt prayer to God for the gift of peace."
The pope said he was offering his "home in the Vatican as a place for this encounter of prayer."
Throughout the trip so far the Vatican has explicitly acknowledged Palestine's new status as a non-member observer state at the United Nations – the same status as that held by the Vatican. It is a status that Canada, the United States, Israel and a few other countries voted against.
While an encounter of prayer is not formal negotiations for a two state solution – like those recently suspended by Israel in the wake of a decision by the Palestinian Authority in the West Bank to form a unity government with Hamas, the ruling party in Gaza – it puts moral pressure on Israel and Palestine's leadership to negotiate seriously, in good faith.
Hamas is classed a terrorist organization in most of the Western world. It refuses to recognize the state of Israel.
Urging constructive negotiations is unmistakably consistent with long-held Vatican policy in favour of two viable states between the Jordan River and the Mediterranean coast. In the mid-70s Pope Paul VI asked Israel to recognize Palestine's legitimate rights and aspirations. When Pope John Paul II visited in 2000 he called conditions in Palestinian refugee camps "barely tolerable." In 2009 Pope Benedict made a point of giving an address standing in front of the three-metre high wall of separation that runs between Bethlehem and Jerusalem.
Sunday morning, Pope Francis prayed silently in front of the wall, then touched and leaned his forehead against the barrier.
After a private meeting with President Abbas early in the morning, Pope Francis' public remarks made the case for continued peace negotiations.
"Peace in security and mutual trust will become the stable frame of reference for confronting and resolving every other problem," said the pope."And thus provide an opportunity for a balanced development, one which can serve as a model for other crisis areas."
Pope Francis spent a good working day in Bethlehem before flying by helicopter to Ben Gurion airport in Tel Aviv for a formal state welcome from President Peres. Under Israel's basic law, the president's role is largely ceremonial.
But before leaving Bethlehem the pope reached out to the many Israeli Arab Christians in the crowd of more than 9,000. As the first pope to visit the Holy Land and not go to Nazareth and Galilee – parts of Israel with substantial Christian populations – Francis sought to reassure the faithful from northern Israel he has not forgotten them.
"My thoughts turn spontaneously to Nazareth, which I hope to visit, God willing, on another occasion," he said.
His final prayer saked Mary to "watch over our families, our young people and our elderly."