As many tele-preachers waded carefully into Egypt’s deepening sectarian discord following clashes between Muslims and Christians that killed eight people recently, Mr. Abdullah put Egypt’s Christians on notice. “Do you think Muslims are cripples? Will they just let you fire? You think we’ll be afraid and run?” he said. “Do not aggravate the Muslims in Egypt.”

The battle here between Islamists and secular-leaning liberals is increasingly fought on the air. The TV sheiks in Egypt attract viewers throughout the Arab world. Mr. Abdullah fields telephone questions from the Persian Gulf, North Africa, Europe and North America. His words are rebroadcast on YouTube, multiplying his global reach.

Nobody knows exactly how many people watch the TV preachers because the Egyptian TV ratings don’t include the rural areas where such shows are most popular. The total viewership of the preachers is believed to be much smaller than the polished productions from more mainstream channels such as Al Hayat, ONTV and CBC. Still, the TV sheiks—most of whom are qualified sheiks in real life—have tremendous influence with certain segments of Egyptian society, and that could be important as the country heads toward another parliamentary election season this fall.

“The channels, they are the soft power of the Salafis,” said Khalil al-Anani, an expert on Islamic movements at Durham University in the U.K. “It’s the main tools to reshape the identity and mind-set of many Egyptians, particularly the low- and lower-middle classes.”