Acts of Peter
"Quo vadis, Domine?" is Latin for "Where are you going, Lord?" and appears in Chapter 69 of the novel in a retelling of a story from the apocryphal Acts of Peter, in which Peter flees Rome but on his way meets Jesus and asks him why he is going to Rome. Jesus says, "If thou desertest my people, I am going to Rome to be crucified a second time", which shames Peter into going back to Rome to accept martyrdom.