Tobias took to guard the woman
Sara and to bring light to the blindness of Tobias; by the insides of the same
fish the demon Asmodeus was driven away from the girl Sara, who is understood
as the church, and blindness was expelled from Tobias. This is the fish, which
in baptism is introduced into the waves of the font, so that what was water may
also be called a fishpool because of the fish. The name of this fish according
to its Greek appellation IKHTHUS contains a host of holy names in its
individual letters, being in Latin Jesus Christ son of God Saviour. This
fishpool, which in the whole catholic church throughout the world abounded with
saving waters for the life of the human race, you translated to serve your own
will, and you dissolved the single baptism, by which the walls are made to
guard human beings, and you made, as it were, other walls, but no good building.
(Optatus of Milevis, Third Book Against the Donatists, in Optatus: Against
the Donatists [trans. Mark Edwards; Translated texts for Historians 27; Liverpool:
Liverpool University Press, 1997], 58-59)
