From twenty years old and upward, all that are able to go forth to war in Israel: thou and Aaron shall number them by their armies.
From twenty years old and upward. The enumeration was confined to those capable of bearing arms, and it was to be made with a careful distinction of the tribe, family, and household to which every individual belonged. By this rule of summation many important advantages were secured-an exact genealogical register was formed-the relative strength of each tribe was ascertained, and the reason found for arranging the order of precedence in march, as well as disposing the different tribes in camp around the tabernacle. The promise of God to Abraham was seen to be fulfilled in the extraordinary increase of his posterity, and provision made for tracing the regular descent of the Messiah.
By their armies - or companies.