(Devarim 20:3) "And he shall say to them "Hear, O Israel … against your foes": and not against your brothers: not Yehudah against Shimon and not Shimon against Yehudah, in which instance if you fell into their hands they would pity you, (viz. II Chronicles 28:8-15) — It is against your foes that you are going, who, if you fall into their hands, will not pity you!
"Let your hearts not faint. Do not fear, and do not tremble, and do not break before them." (He warned them) against the four things that the enemy did in war: clashing, trumpeting, shouting, and tramping. "Let your hearts not faint" at the whinnying of the horses and the flashing of the swords. "and do not fear" the clashing of the shields and the tramping of the shoes. "and do not tremble" at the blaring of the trumpets. "and do not break" before the cries (of battle). "For the L-rd your G-d goes with you": They come with the "triumph" of flesh and blood, and you come with the triumph of the L-rd.