saying to them, “Hear, O Israel, today you are going into battle with your enemies. Do not be fainthearted or afraid; do not be alarmed or terrified because of them.
Israel was at this time to be considered rather as a camp than as a kingdom, entering upon an enemy's country, and not yet settled in a country of their own; and, besides the war they were now entering upon in order to their settlement, even after their settlement they could neither protect nor enlarge their coast without hearing the alarms of war.
Commenting on Deuteronomy 20:1-9
And shall say unto them, hear, O Israel,.... Exciting their attention to what he was about to say, and which, as Jarchi observes, was spoken in the holy tongue, or in the Hebrew language: you approach this day unto battle against your enemies; were marching or ready to march, preparing to engage with them, and a battle seemed near at hand: let not your hearts...
Deu 20:2-4 If they were thus drawing near to war, i.e., arranging themselves for war for the purpose of being mustered and marching in order into the battle (not just as the battle was commencing), the priest was to address the warriors, and infuse courage into them by pointing to the help of the Lord.
Commenting on Deuteronomy 20:2-4