When you go out to war against your enemies, and see horses and chariots and an army larger than your own, you shall not be afraid of them, for the LORD your God is with you, who brought you up out of the land of Egypt.
When the Israelites invaded Canaan they faced enemies who were stronger than they were. They won only because God helped them.
Israel was a nation and like any other nation it sometimes waged wars with other nations. The church isn’t a nation but is a body of people from all nations who have put their faith in Jesus Christ. Because we aren’t a nation we don’t have an army and we don’t engage in physical wars but we are involved in warfare of a different kind.
After Gideon raised an army to battle the Midianites the first thing God did was reduce the size of it so they wouldn’t think that they had won a victory by their own power. The first step in this reduction was to send home all those who are afraid. This eliminated 22,000 of the soldiers and left only 10,000.