From Greek letter chi (Χ), which visually crosses. A chiasm (or chiastic structure) is a literary technique in which the second half of a passage mirrors the first half in reverse order: A-B-C-B'-A'. The central element of the chiasm (C in this example) often carries the primary theological emphasis. Chiastic structure is found throughout the Hebrew Bible and the New Testament, reflecting ancient Near Eastern and Greco-Roman literary conventions that prized symmetry and rhetorical balance.
Examples clarify. Genesis 12:1-3 is chiastic: (A) Go from your country; (B) to the land I will show; (C) I will bless you; (B') the nations shall be blessed; (A') through you all families. The central thrust: blessing. Numbers 6:24-26 — the Aaronic blessing — is chiastic around the Name of the LORD. Major books use large-scale chiasms: Deuteronomy, Leviticus (arranged around the Day of Atonement in chapter 16), Isaiah, Matthew. Matthew's Sermon on the Mount may be chiastic around the Lord's Prayer. Mark's Gospel has often been analyzed as a chiasm with the Transfiguration at the center. Three payoffs of recognizing chiasm. (1) Identifies the author's emphasis. Find the center of the chiasm and you often find the text's main point. (2) Validates structural unity. Passages skeptics claim are "disjointed" often display tight chiastic order, showing authorial intent. (3) Enhances memory. Chiasms are aides-mémoire in oral cultures; their symmetry helps a hearer retain the passage accurately. Careful Bible readers learn to look for chiastic patterns — they reveal interpretive keys invisible to a merely linear reading.