Moments before the beheading of 21 Egyptian Christians, an Islamic State leader warned "Crusaders" that this rite was being held on a North African beach for a reason.

Previous videos of ISIS fighters "chopping off the heads that have been carrying the cross for a long time" were filmed in Iraq and Syria, he noted, in fluent English. "Today, we are … south of Rome, on the land of Islam, Libya, sending another message."

When the slaughter was over, the lead executioner stressed again: "We will conquer Rome, by Allah's permission."

Time after time, Pope Francis has refused to take this bait -- consistently stating his conviction that true Islam promotes peace, not violence. He said this again when a reporter asked about the murder of the elderly Father Jacques Hamel in France.

"I don't like to speak of Islamic violence," said Francis, flying home from World Youth Day in Poland. "When I browse the newspapers, I see violence, here in Italy -- this one who has murdered his girlfriend, another who has murdered the mother-in-law -- and these are baptized Catholics! …

"If I speak of Islamic violence, I must speak of Catholic violence. … Not all Muslims are violent, not all Catholics are violent. It is like a fruit salad -- there's everything."

The terrorists who slaughtered the Egyptian Christians, he added, were quick to "show us their identity cards" as part of the Islamic State. "But this is a fundamentalist group which is called 'ISIS.' But you cannot say -- I do not believe -- that it is true or right that Islam is terrorist."

The pope's stand has caused debate among Catholics and other Christians, as well as quiet tensions with Christians in the ancient Middle Eastern churches. However, he has drawn praise from mainstream Islamic leaders, who stress the fact that ISIS has massacred countless Muslims who have rejected its radical vision of the faith.

Now, in a new issue of its magazine Dabiq -- entitled "Break the Cross" -- ISIS has responded directly to the pope of Rome, arguing that Francis has been misled by Muslims who are themselves heretics.