Minya became synonymous with violence against Coptic Christians in the summer of 2013 after the military, led by Mr. Sisi, ousted the country’s elected Islamist president, Mohamed Morsi, who was a leader of the Muslim Brotherhood. Mobs of young men attacked Christian homes, churches and businesses in the province, driven by suspicions among the Muslim Brotherhood that Copts had conspired with the military to oust Mr. Morsi.

Copts, who make up about 10 percent of Egypt’s 90 million people, have for decades complained of discrimination. Mr. Naguib said he feared that the growing atmosphere of intolerance in the country could hurt his clients’ chances of a successful appeal.

Image An undated image of the writer, Ahmed Nagy. Mr. Nagy was given a two-year sentence for publishing an excerpt from his novel in a magazine that was deemed to have offended public morals. Credit... Yasmin Hosam El Din/Associated Press

“How can we be optimistic in a climate where everything is taken so sensitively?” said Mr. Naguib.

In the video, one of the students is shown kneeling on the ground, pretending to recite verses from the Quran, as his friends stand laughing behind him. At one point, one of the four places a hand under the neck of another, as if to behead him.

The clip was filmed by one of their teachers, also a Christian. He has been convicted on charges of contempt of Islam in a separate trial in relation to the same incident.

A year ago, Mr. Sisi, in an address to Egypt’s clerical leaders, urged them to purge Islam of the ideas that encourage violence and have made the religion “an enemy of the world.” But since then, the courts have often focused on cases that impinge on civil rights, including free speech.

In January, a Cairo court sentenced a poet, Fatma Naoot, to three years in jail for a Facebook post that criticized the slaughter of animals for the Muslim feast of Eid al-Adha. Weeks earlier, Islam Behery, a television presenter with a wide following, was jailed for a year for broadcasts that challenged Muslim orthodoxy.