3. Aaron shall number them by their armies—or companies. In their departure from Egypt they were divided into five grand companies (Ex 13:18), but from the sojourn in the wilderness to the passage of the Jordan, they were formed into four great divisions. The latter is here referred to.

     21-23. Israel sent messengers unto Sihon—The rejection of their respectful and pacific message was resented—Sihon was discomfited in battle—and Israel obtained by right of conquest the whole of the Amorite dominions.