The noun diēgēsis refers to a full narrative or detailed account. Remarkably, it appears only once in the New Testament — in the opening verse of Luke's Gospel (1:1), where it refers to the 'orderly account' that many had already attempted to write about Jesus's life and ministry.
Luke 1:1's use of diēgēsis is the New Testament's most explicit statement of its own literary method: the Gospel is a historical narrative, not a myth or allegory. Luke positions himself as a careful historian who investigated sources, interviewed witnesses, and produced an 'orderly account' (kathexēs) for Theophilus. This self-conscious historiography grounds Christian faith in real events — the incarnation, death, and resurrection of Jesus are not symbols but history.