Paul Gaechter, Jesuit, born 1893, is an emeritus professor of the University of Innsbruck. He became well known through his publications regarding “Mary’s Earth Life” (3rd ed., 1955) and “Peter and His Time” (1958). Furthermore, he published a large commentary on the first Gospel (1964).
In rhetoric, chiasmus (/kaɪˈæzməs/ ky-AZ-məs) or, less commonly, chiasm (Latin term from Greek χίασμα, "crossing", from the Greek χιάζω, chiázō, "to shape like the letter Χ"), is a "reversal of grammatical structures in successive phrases or clauses".
A chiasm (otherwise known as chiasmus) is a literary device that presents a series of ideas, and then repeats them in opposite order.
Chiastic structure is often expressed in letters. An example of this structure is idea A and idea B, followed by idea B' and idea A'. B' and A' are the same ideas as B and A, but in reverse order creating ABB'A'.
The goal of chiastic structure is to create emphasis, repetition, or clarification. The term 'chi' comes from the Greek letter 'chi,' which looks like the letter 'X' in English.
Chiasm in Sumero-Akkadian by R Smith
Chiasm in Ugaritic by John W. Welch
Chiasmus in Hebrew Biblical Narrative by Yehuda T. Radday
Chiastic Patterns in Biblical Hebrew Poetry by Wilfred G.E. Watson
Structure and Chiasm in Aramaic Contracts and Letters by Bezalel Porten
Chiasmus in Talmudic-Aggadic Narrative by Jonah Fraenkel
Chiasmus is closely related to another figure of speech called antimetabole. They're so similar, in fact, that the term chiasmus is often used to describe things that are actually examples of antimetabole. Here are the key differences between the two terms, summarized:
Antimetabole involves the inverted repetition of words or phrases.
Chiasmus involves the repetition of similar concepts within a repeated and inverted grammatical structure, but not necessarily the repetition of the same words.
An example of antimetabole would be, "It's nice to be important but it's more important to be nice."