וַנַּחֲרֵ֣ם אוֹתָ֔ם כַּאֲשֶׁ֣ר עָשִׂ֔ינוּ לְסִיחֹ֖ן מֶ֣לֶךְ חֶשְׁבּ֑וֹן הַחֲרֵם֙ כָּל־עִ֣יר מְתִ֔ם הַנָּשִׁ֖ים וְהַטָּֽף׃
Y destruímoslas, como hicimos á Sehón rey de Hesbón, destruyendo en toda ciudad hombres, mujeres, y niños.
Rabbeinu Bahya
We know that Moses fulfilled the role of that angel during his own lifetime from the fact that whenever he raised his hands in supplication the Jewish people succeeded in driving back Amalek (Exodus 17,11). When this angel materialized before the eyes of Joshua with a drawn sword in his hand he made it amply clear what his function was to be. When, subsequently, we read in the Book of Joshua (10,11) of gigantic rocks dropping out of the sky (heaven) upon the fleeing Canaanites this was part of that angel’s doing. When the kings were killed (Joshua 10,28) the description of the utter destruction wrought upon all the living souls in these various cities was beyond anything Moses had done during his own lifetime. When Moses conducted war the Torah mentions that the victims’ bodies were destroyed. We never find, as we do constantly in the Book of Joshua, that the souls of the victims were destroyed also (contrast description of Deut. 3,6 with Joshua 10,28-39). In order that we do not misunderstand the word נפש in those verses as applying only to the animalistic life-force of the Canaanites, we are told in Joshua 10,40 ואת כל הנשמה החרים, “he utterly wiped out every soul.” This was why this angel had to accompany Joshua on his campaign.