Chiasmus

Chiasmus (or chiasm) is a literary device in which two or more clauses are repeated in reverse order, and for which the inverted clauses may be either parallel to or in contrast to the corresponding clause in the first part of the chiasmus. To display a chiastic structure, the text is sometimes presented in outline form, such as "A B C X C' B' A", where the "X" represents the center of the chiasm. It is sometimes stated that the center of the chiasm marked a place of special emphasis, but this is not always the case. Sometimes, especially in small chiasms, there may be no "X" center.

Simple examples of Chiasmus
"Enemies in War, in Peace Friends." (A B B' A'; antithetical chiasmus from the Declaration of Independence) "But many who are first will be last, and many who are last will be first" (A B B' A'; Matthew 19:30, NIV).

Chiasmus forgotten until fairly recently
Chiasm was used as a literary device in the ancient world, in Babylonia, Israel, Greece, and Rome. It fell out of use, however, and in modern times the existence of chiasms in ancient literature was only recognized by a few scholars in the 18th and 19th centuries. This changed in the middle of the twentieth century, when Nils Wilhelm Lund wrote Chiasmus in the New Testament. "Since these seminal studies the study of New Testament chiasm has blossomed, until today recognition of chiastic structure is common in full-scale commentaries and other scholarly works. The study of Old Testament chiasms has likewise begun to come of age."

The Chiasmus of the Flood Account
Early rationalist critics of the Bible, unaware of the literary methods of antiquity (and often unwilling to learn from ancient sources because doing so would threaten their presupposition-based theories), missed completely the chiastic structures that are used in the Scripture. The most elegant and complete of all chiastic structures in the Bible is that of the account of the Flood, found in Genesis 6:10 to 9:19. The entry of people and animals into the ark, followed by the rise of the Flood waters, then their fall, then the exit of people and animals, perhaps suggested a chiastic structure to the original author or authors. The Genesis Flood narrative is one of the most artistic examples of this literary device from all of antiquity. The Flood chiasm is presented here as adapted freely from a 1978 article by Gordon Wenham.

Within this overall structure, there is a numerical mini-chiasm of 7s, 40s, and 150s:

The two mentions of 150 days refer to the same period, and the first 40 days (7:13,17) are part of the 150 days. All this is consistent with the date in 8:4. Notice that there was no compelling reason to repeat the first 7-day figure of waiting to enter the Ark except for the corresponding two 7-day figures for the dove, nor was there any reason to repeat the 150 days except for the chiasmus. The chiastic structure explains the repetition of all these figures, whereas the radical critics, with their low view of the inspiration of Scripture, thought the repetition implied different authors or redactors putting something together from diverse and disagreeing accounts from long before their time.

The Flood account in light of the Tablet theory
The Flood account, however, is not a patchwork put together by late-date editors. The artistic structure of the account shows conscious design by one author, or, alternately, by the three sons of Noah who were working closely together to record the toledoth of the Flood (Genesis 10:1, 11:10a). If Percy Wiseman's Tablet theory is true, then the account of the Flood was written by survivors of the Flood. The entire account of the flood is within the toledoth of Shem, Ham, and Japheth that ends at Genesis 9:10. Later, Shem, who may have outlived his brothers, finished his own toledoth at Genesis 10:10a. This interpretation of the literary structure of the first 36 chapters of Genesis would make the Flood chiasm, with high probability, the oldest of all chiasms. As such, its example created this literary technique that was followed for thousands of years in the literature of the ancient world.