That He prohibited us from being afraid of the enemies during the time of war, and that we not run away from them. Rather, it is an obligation upon us to be resilient and to stand firm and be strong against the other people. And anyone who retreats and runs away has already transgressed this negative commandment. And that is His, may He be exalted, saying, "You shalt not be terrified by them" (Deuteronomy 7:21). And this prohibition was repeated when He said, "Do not fear them" (Deuteronomy 3:22). And this command was repeated frequently - not to run away and not to retreat during the time of war - since it is possible to confirm the true faith with this matter. And the regulations of this commandment have already been explained in the eighth [chapter] of Sotah. (See Parashat Ekev; Mishneh Torah, Kings and Wars 7.)