- Rarely since the first century have Christians faced persecution on this scale, say Dolan, Downey and Burnett.
- Crisis escalated substantially as ISIS has swept through Iraq's Nineveh province, the authors write.
Cardinal Timothy Dolan is the archbishop of New York, Roma Downey and Mark Burnett are honorary chairpersons of The Cradle Fund and the producers of " A.D. -- The Bible Continues," which chronicles the rise of the church in the face of persecution. The views expressed in this column belong to Dolan, Downey and Burnett.
(CNN)This is the time of the year when Christians the world over -- more than 2 billion of us -- reflect upon the crucifixion and resurrection of our Lord.