As the Reverend Ken Newell, a prominent Presbyterian evangelical, spoke on BBC Radio Ulster in 1981 about his commitment to peace in Northern Ireland, he had no idea that members of the Redemptorist Order at Clonard Monastery in West Belfast were listening in.

The Redemptorists also had been praying and working for peace. The order contacted Newell within days, but it wasn't until Father Gerry Reynolds came to work for the order that the two men met.

They became fast friends. Over the years, their friendship deepened as both realized, more than their own traditions would allow, that in each other they had found a brother in the Lord.

Reynolds took Jesus' words, "Love one another as I have loved you," to heart. "We determined to set an example of Christian friendship," he says. "There was nothing we could not talk about nor ask one another to do."

The friendship also broadened as the men realized the potential this bond held for their respective communities—and for peace.

Newell brought his own community along on this journey, and most parishioners at Fitzroy Presbyterian Church welcomed the link with the Catholic community of his new friend. Reynolds brought his fellow monks into fellowship with these (somewhat odd for them) Bible-carrying, chorus-singing Protestants.

The result was The Clonard Fitzroy Fellowship, which linked the Presbyterian parish and the Catholic monastery in ventures ranging from Bible studies to active work in political peacemaking.

Reynolds and his colleagues, especially the self-effacing Father Alex Reid, were directly involved in back-channel talks that brought together politicians representing warring communities. Long before politicians from Sinn Fein (typically Catholic, favoring Irish nationalism) ...