Deuteronomy 7:21 "You shall not be terrified by them"

When a Jewish soldier is called up to the battlefront, he should trust in HaShem. He should realize that he is fighting for the sake of the Master of the Universe.

The Jewish soldier is commanded not to fear the enemy. He must gather all his courage and rely on HaShem to protect him.

Whoever retreats from the enemy because of fear violates this Negative Mitzvah.