Old Testament scholar Richard Hess has written in great detail about the Canaanite question, and he offers further important insights on this topic. He argues persuasively that the Canaanites targeted [by Israel] for destruction were political leaders and their armies rather than noncombatants. For example, Deuteronomy 20:10-18 mentions the “ban” or “dedication to destruction” (herem, its verb form is haram), which refers to the complete destruction of all warriors in the battle rather than noncombatants.
However, doesn’t Joshua 6:21 mention the ban—every living thing in it—in connection with men and women, young and old, ox, sheep, and donkeys? This stock phrase “men and women” occurs seven times in the Old Testament in connection with Ai (Josh. 8:25); Amalek (1 Sam. 15:3); Saul at Nob (1 Sam. 22:19…); Jerusalem during Ezra’s time (Neh. 8:2); and Israel (2 Sam. 6:19, 2 Chron. 16:3). Each time—except at Nob, where Saul killed the entire priestly family except one (1 Sam. 22:20)—the word “all” (kol) is used.
The same applies to earlier passages in Deuteronomy: “we captured all his cities at that time and utterly destroyed the men, women and children of every city. We left no survivor” (2:34); and again, “utterly destroying the men, women, and children of every city” (3:6). The expression “men and women” or similar phrases appear to be stereotypical [i.e. traditional rhetorical formulas not necessarily meant to be taken literally, cp. “lock, stock, and barrel” or “hook, line, and sinker”] for describing all the inhabitants of a town or region, “without predisposing the reader to assume anything further about their ages or even their genders…” The use of “woman” and “young and old” were merely stock ancient Near Eastern language that could be used even if women and young and old weren’t living there. The language of “all” (“men and women”) at Jericho and Ai is a “stereotypical expression for the destruction of all human life in the fort, presumably composed entirely of combatants.” The text doesn’t require that women and young and old must have been in these cities.
Paul Copan, Is God a Moral Monster? (Baker Books: 2011)
For those interested in pursuing this line of thought further, I recommend the work of Dr. Matthew Flannagan—specifically his three part series on the apparent genocide in the Old Testament (Part 1, Part 2, Part 3). Additionally, Dr. Flannagan has analyzed Saul’s experience in 1 Samuel 15 specifically against this wider interpretive backdrop, and that article is available here.