After a long prophetic introduction that duplicates earlier material (verses 15b-16), the rest of Balaam’s fourth oracle appears to adopt a chiastic structure as follows:
Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .