St. Jerome, who tells us that he translated the Book of Tobit from Greek into Latin in the course of a single night, was intrigued by that dog. Although he must have been pretty tired as he came to the end of his candlelight labor during the morning hours, Jerome was still sufficiently alert to do something rather imaginative with that dog. He actually altered the text of the Book of Tobit, a thing he felt free to do, since he did not believe the book to be canonical (a distinctly eccentric view among the Latin Fathers, be it noted). Jerome inserted a detail—or, more accurately, a tail—in the Vulgate’s description of Tobias’s return: “Then the dog, which had been with them in the way, ran before, and coming as if it had brought the news, showed his joy by fawning and wagging his tail.” Neither that tail nor its wagging is found in the Septuagint version of Tobit. Jerome made it all up.
It is not difficult to discern why the prankish Jerome engaged in this little witticism. Struck by the story’s resemblance to Homer’s Odyssey, which also tells of a man’s journey back to the home of his father, Jerome remembered Argus, the dog of Odysseus, the first friend to recognize that ancient traveler on his return to Ithaca. The old and weakened Argus, Homer wrote, when he recognized his master’s voice, “endeavored to wag his tail” (Odyssey 17.302).
There was more than a joke involved here, however. Jerome correctly regarded the trip of Tobias, like the travels of Odysseus, as a symbol of man’s journey through this world, returning to the paternal home. Tobias thus takes his place with Gilgamesh, Theseus, Jason and the Argonauts, Aeneas, and the other great travelers of literature. It is the Bible’s teaching that we do not make this trip alone. We are accompanied by “an angel of peace, a faithful guide, a guardian of our souls and bodies.”
Fr Patrick Reardon, Christ in His Saints, 278