With every literary genre or form come some conventional expectations that the biblical authors either follow or deviate from.
Craig BlombergIn the New Testament alone there are Gospels, acts, epistles, and an apocalypse. Gospels contain literary forms like miracles, parables, pronouncements, proverbs, farewell discourses, annunciations, and so on. Epistles can be apologetic, commendatory, friendship-oriented, exhortational, diatribes.
Craig Blomberg