Pope Benedict has urged Middle Eastern Christians to work for peace and against "the grim trail of death and destruction" in the world, in a sermon delivered in Lebanon.
He was speaking at an open-air mass attended by 350,000 worshippers, and leaders of Lebanon's Christian and Muslim communities, including from the militant Shia group Hezbollah.
Peace between warring factions and religious groups in the Middle East has been a central theme of his visit, along with his call to Christians not to leave the region despite war and pressure from radical Islamists.
Lebanon, torn apart by a 1975-1990 sectarian civil war, is a religious mosaic of more than four million people whose Muslim majority includes Sunnis, Shia, Alawites and Druze.
About a third of the population is Christian, divided into more than a dozen churches.
"In a world where violence constantly leaves behind its grim trail of death and destruction, to serve justice and peace is urgently necessary," Pope Benedict said at the mass, praying for: "Middle East servants of peace and reconciliation".
"This is an essential testimony which Christians must render here, in cooperation with all people of good will," he said.
The pope appealed on Friday for an end to the import of weapons into Syria, branding it a "grave sin" and saying a halt to the arms flow could help end the civil war.
Activists say more than 27,000 people have been killed in Syria's 18-month-old mainly Sunni Muslim uprising against President Bashar al-Assad, who belongs to the minority Alawite sect that grew out of Shia Islam.
Few of Syria's Christians, about 10% of Syria's population, have joined the uprising against Mr Assad, fearing that it could bring hostile Islamists to power in Damascus.
Politicians from all sectors of multi-faith Lebanon attended the mass, held on reclaimed land next to the port. Leaders of the country's main religions all assured the Vatican of their support for the visit in advance.
With no shade from the hot sun for the crowd, many fanned themselves as temperatures rose over 30C. The 85-year-old pope was seen mopping sweat from his forehead at one point although the altar was under a canopy.
Red Cross workers carried away at least two worshippers who fainted from the heat halfway through the celebration.
There were some pre-visit concerns about security because of a wave of protests across the Muslim world against an anti-Islam film produced in the United States. One protester was killed on Friday in violence in the northern Lebanese city of Tripoli.
