Few people can be completely without fear at the moment at the unpredictable and uncontrollable terror threat confronting the world.
In particular, Catholics in Britain can identify with what Muslims are going through because many can remember what it was like for them when IRA bombing campaigns were at their height, according to the Archbishop of Westminster.
"This is something that the Catholic community understands in the light of the experience of the effect of IRA bombings on relationships in society when those things were happening," Cardinal Vincent Nichols told Christian Today.
Talking after a meeting of the Council of Christians and Jews at Lambeth Palace, the London home of the Archbishop of Canterbury, Cardinal Nichols said Muslim leaders are worried about the "possible hostile reaction" light of what is being done by ISIS. "We just wanted to add a voice of support for those communities at this very vulnerable time," the Archbishop said. "To perpetrate violence in the name of God is blasphemy."
According to Cardinal Nichols, everybody is frightened, including Muslims. ISIS have killed far more Muslims than people of other religions, he added. This is not Muslim versus Christian, but "an extremist movement against the rest." He said it was an objective of the terrorists to sow fear, hatred and division.
Knee-jerk reactions against Islam and Muslims must be resisted. Christians, with a long history of nuturing interfaith relations, are in the prime position to give a lead on this.
Christian leaders have bravely resisted a defensive response. Instead, at their meeting in Leeds this week, the Catholic bishops of England and Wales called for the Government's plans to resettle 20,000 Syrian refugees in the UK to be extended to even more of the millions of displaced people.
In holding out the hand of welcome to refugees, the Catholic bishops of England and Wales are not welcoming potential jihadists into the UK, as some might fear. Instead, they want to welcome legions of terrified people, mainly other Muslims, fleeing from the very same threat that is so unnerving our own society.
"The barbarous attacks in Paris last week should not deter us from caring for those in need." the bishops said. Their approach mirrors that of the US Catholic bishops who this week strongly opposed calls for Christian refugees only to be admitted to the United States.
The Council of Christians and Jews has long experience negotiating these tricky waters. The council was key in helping broker a peace between Judaism and Christianity in the aftermath of the atrocities of the Second World War when six million Jews were slaughtered in the Nazi holocaust.
The generosity of the commonal faith response, including Muslims, to live out a literal expression of the Catholic social teaching of the "common good", is the true face of these three great faiths.
For me, one of the most revelatory aspects of the Paris terror attacks was the discovery of drugs paraphernalia inside the hotel room used by the bombers.
Syria is known to be producing vast quantities of amphetamines, and captured ISIS fighters have described being dosed with drugs to turn them into murderous jihadists who feel no fear or pain, completely without conscience.
It does not detract from the absolute horror but for me it takes away some of the fear. The belief that religious indoctrination was enough to turn young men and women into monsters like those Paris bombers was terrifying. It was especially puzzling given how many of them seem to have had little or no interest in fundamentalist religion in their earlier lives.
But if in fact this is not in fact the case, and ISIS can only create its armies of suicide bombers by first making them into drug addicts, that is something else. Drug use for any ends, let alone these, completely subverts the Prophet's prohibition on all intoxicants. It is wholly unIslamic. And it means there is a terrible weakness there to be exploited by all who are fighting to counter this threat.
Many recovering addicts and alcoholics describe their past behaviour as a form of chronic suicide. Addiction can give rise to, and then fuel, a death wish.
If we ask what Jesus or Mohammed would have done, they would be with the faith leaders and the refugees. There is no God of any religion that would be with these drug-addled maniacs bringing chaos to cities, death and fear into our lives. As Cardinal Nichols and the other faith leaders have said, there is nothing Islamic about ISIS apart from the group's hijacking of the name of the religion. Faith is an antidote to fear. We can keep our faith and win this war because fundamentally, ISIS is weak.