The narrator says that Father Arsenios is saved by the war. He gradually realizes that God failed Greece and takes it upon himself to save his country. He adopts a dog and starts walking and preaching. The Germans ignore him, but the Italians listen with wide eyes to his words that they don't understand. After two years of traversing the island and preaching, Arsenios becomes skeletally thin. He's happy for the first time in his life and the narrator notes that had Arsenios lived, he might've become a saint.
When the narrator notes that the war saves Father Arsenios, it suggests that there are ways for individuals to find purpose in such horrific times. The fact that the Italians listen to Arsenios shows that they're more than willing to humanize and respect the Greeks, which makes the Italians read as more human and sympathetic.