Ruth Abah, 28, no longer walks to her local church, St. Paul’s, which now lies in ashes. Instead, the mother of two locks her doors and prays with her children, fearful the next attack could come at any moment. On Aug. 11, suspected Fulani herdsmen stormed the compound of the Catholic church in the village of Aye-Twar, in central Nigeria, setting the church, rectory and parish offices ablaze along with vehicles and other property. Earlier raids had already forced the parish’s 26 outstatio...