CAIRO -- He was young and bright, with an education from Egypt's premier school of Islamic studies and lucrative job offers in the Gulf. But Bilal Farag chose a different path, friends say, one that led him to die on a distant Syrian battlefield, fighting Shiite Muslims he regarded as infidels.
"Everybody has their own goal in life," said a close friend, Hosam Ali. "Bilal's was to be a martyr."
Waves of Egyptians are now preparing to follow, fired by the virulently sectarian rhetoric of Sunni preachers and encouraged by the newly permissive policies of Egypt's Islamist government. In recent days, this city's ancient mosques have crackled with calls for jihad, as hard-line Sunni Muslim leaders command the faithful to respond to recent escalations in Syria by the Shiite forces of Iran and Hezbollah.
The Sunni backlash has echoed far beyond Egypt, penetrating every corner of the region, where divisions between the rival Muslim sects are hardening fast. At Saudi Arabia's Grand Mosque in Mecca, Islam's holiest site, the top cleric broke down in tears on pan-Arab television last week as he pleaded with fellow Muslims to aid Syrian rebels "by all means."
The prospect of a fresh flow of radicalized fighters bent on waging sectarian war threatens to complicate the Obama administration's recently announced strategy to arm the rebellion's moderate factions.
Although the United States and the Sunni jihadis share a common enemy -- the government of Syrian President Bashar al-Assad, whose Alawite sect represents an off-shoot of Shiite Islam -- they have starkly different motivations. The United States is hoping to strengthen the rebels' hand in advance of possible peace talks and to marginalize radical groups. Many foreign fighters, meanwhile, are seeking to defeat what they consider a deviant strain of Islam that they believe has declared war on the religion's true adherents.
The vast majority of Egyptian Muslims are Sunni, but until recently, Egypt had sought to stay on the Syrian war sidelines. It was part of a shrinking middle ground in an increasingly polarized region. Its Muslim Brotherhood-aligned president, Mohamed Morsi, had avoided sectarian rhetoric and even carved out a potential mediating role by cultivating closer ties with Iran.
That changed Saturday night. Mr. Morsi, who has been under pressure from hard-line Islamists at home, used a stadium speech before thousands of supporters to rip into Mr. Assad, Hezbollah and Iran. As the crowd chanted, "Sunni blood isn't cheap," the president announced that he was cutting all ties with Damascus, and that Egypt would provide support for the rebels.