A literary genre may be defined as a group of texts that exhibit a coherent and recurring configuration of literary features involving form (including structure and style), content, and function. Literary forms, on the other hand, while exhibiting similar recurring literary features, are primarily constituent elements of the genres that frame them.
Literary genres and forms are not simply neutral containers used as convenient ways to package various types of written communication. They are social conventions that provide contextual meaning for the smaller units of language and text they enclose. The original significance that a literary text had for both author and reader is tied to the genre of that text, so that the meaning of the part is dependent upon the meaning of the whole.
David Aune The New Testament in Its Literary Environment
Our stance about the literary genre of a book determines our entire interpretation of the book.
Genre plays a positive role as a hermeneutical device for determining the sensus literalis or intended meaning of the text. Genre is more than a means of classifying literary types; it is a epistemological tool for unlocking meaning in individual texts.
Apart from a correct analysis of the literary form of a text and an application of the rules governing that genre, a correct understanding of the author’s meaning is impossible.
In contrast to the dreams and visions of the prophets, which stand in need of interpretation, the message to Moses is communicated in a clear and straightforward manner [i.e. v. 6, “clearly and not in riddles”], such as in the giving of the Law. This verse [Num. 12:6-8] implicitly instructs readers to adopt a different hermeneutics for interpreting material attributed as spoken direct to Moses in contradistinction to the prophetic material. The legal material addressed to Moses is plain and straightforward; the prophetic materials require more rumination, for the are in the form of idles and allegory, with a dreamlike, symbolic quality. This symbolic quality becomes even more exacerbated in apocalyptic literature, such as Daniel and Revelation.
Bruce K. Waltke Old Testament Theology (pg. 47)