Deuteronomy 20 · a question people ask
Could a man really go home before the battle just because he was afraid?
As the chapter gives it, yes. After the three who had begun something and not yet finished it (20:5-7), the officers ask one more question: "What man is there who is fearful and faint-hearted? Let him go and return to his house, lest his brother’s heart melt as his heart" (20:8). The reason given is not about him but about his brother. Only after this are captains appointed (20:9). Judges tells of the fearful going home before a battle. Before Gideon's battle the LORD said the people with him were too many, "lest Israel brag against me" (Judges 7:2), and the call went out, "Whoever is fearful and trembling, let him return" (Judges 7:3). "So twenty-two thousand of the people returned, and ten thousand remained" (Judges 7:3). The chapter's own answer to fear comes before this, in the priest's words: "the LORD your God is he who goes with you" (20:4).
The verses
“The LORD said to Gideon, “The people who are with you are too many for me to give the Midianites into their hand, lest Israel brag against me, saying, ‘My own hand has saved me.’ Now therefore proclaim in the ears of the people, saying, ‘Whoever is fearful and trembling, let him return and depart from Mount Gilead.’” So twenty-two thousand of the people returned, and ten thousand remained.”