1) Expression 2) Locution 3) Saying 
[n] - a saying of Jesus that is regarded as authentic although it is not recorded in the Gospels
logion (s); logia, (pl) Maxim of a religious teacher or some other significant saying; especially, a saying of Jesus unrecorded in the Gospels (or one of the so-called agrapha) or one of certain sayings of Mohammed.
noun a saying of Jesus that is regarded as authentic although it is not recorded in the Gospels
a traditional saying or maxim, as of a religious teacher. · (sometimes cap.) · a saying of Jesus, esp. one contained in collections supposed to have been among the sources of the present Gospels. · a saying included in the agrapha.