Deuteronomy 20 describes laws concerning warfare. Israel were about to face many battles while entering the promised land, fighting against nations known for their military prowess. Moses tells Israel, “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… Do not fear or panic or be in dread of them, for the Lord your God is he who goes with you to fight for you against your enemies, to give you the victory”.
Israel had good reason to be afraid; from a natural standpoint they had no chance of defeating the Canaanites. With God fighting on their behalf though, their victory was assured. This language is very similar to language used to describe our battle against sin. Ephesians 6, “Be strong in the Lord and in the strength of His might”. 2 Corinthians 10, “For the weapons of our warfare are not of the flesh but have divine power to destroy strongholds”. 1 Corinthians 15, “Thanks be to God, who gives us the victory through our Lord Jesus Christ.”
The war is already won, we just need to fight our daily battles against sin, confident that God is on our side.