“Paul, Apostle of Christ” comes from the Affirm label, which has produced such Christian-themed dramas as “Heaven Is for Real.” Less interested in blunt proselytizing than more open-ended explorations of faith and its challenges, Affirm films have gratifyingly avoided the kind of Sunday-school pageantry that characterizes so many movies of the genre. “Paul, Apostle of Christ” is no exception. A portrait of the titular Christian convert and leader of the early church as he faces imprisonment and martyrdom at the hands of Roman oppressors, this absorbing drama benefits from lush production values and first-rate performances from a cast of seasoned...