Verse 13 repeats the information in verses 11-12; the main body of troops is north of Ai, and the smaller body (literally “the heel”) is west of the city. New English Bible, following the Septuagint, omits verse 13. At the end of the verse the Masoretic text has “and Joshua went that night into the valley”; some Hebrew manuscripts, however, have the verb “to spend the night,” which is preferable by most translations. Hebrew Old Testament Text Project, however, prefers to follow the Masoretic text, in which case one may translate “Joshua himself returned during the night to the Jordan Valley.”

Quoted with permission from Bratcher, Robert G. and Newman, Barclay M. A Handbook on Joshua. (UBS Helps for Translators). New York: UBS, 1983. For this and other handbooks for translators see here .