Summary: This was the Lord of Host's battle, and His victory. The strategy was unconventional, but effective, and a reminder of the holy wrath of God upon wickedness.
God is depicted in the Book of Joshua as a Warrior--One who leads His people into battle and gives them victory. Throughout Scripture, God is referred to as the “Lord of Hosts,” literally “armies.” Joshua engaged the enemy in the Name and power of God, a holy conflict. Israel was a theocracy and was given specific instructions for the conquest of Canaan, with rules of engagement. This was a just-war against an irredeemable people who rivaled Sodom and Gomorrah in their depravity. God would use His chosen people to bring judgment upon them...otherwise their morally bankrupt culture would corrupt Israel to follow after their detestable practices, like idol worship, child sacrifice & incest. The Holy Land wasn't very holy.
The Canaanites had been warned and were morally accountable. “God’s wrath is preceded by His patience” (David Wells). Canaan's sins had reached their limit. The military objective, however, was to drive them out, not annihilate them. Mercy was given to any who responded positively to the God of Israel. Some, like Rahab, were taken in. Those who remained were killed. Such drastic action as Israel carried out is an unrepeatable command for a specific purpose, not warranted without special revelation directly from God.
We read in the Ten Commandments, “Thou shalt not commit murder.” War is not murder, and should not be confused with personal hatred and retaliation. Not all killing is unlawful. In war, the antagonist is not a personal enemy but a lawbreaker who is to be punished by the insistence of society. Soldiers serve by governmental authority, which is established by God (Romans 13). While nations have the right to wage war to defend themselves and their neighbors, this doesn't guarantee that God is “on their side.” Not all wars are just; not all causes are holy. In Jericho, “God the Warrior, fought through the fighting of His people” (Peter Craigie). “When the cause is just, it is virtuous to fight well in battle” (Darrell Cole).
The city of Jericho was a fortress, tightly secured. It had both an inner and outer wall. It was built to defend the eastern approach to Canaan, and could not be bypassed. I took 40 people from Germany to Israel in 1989 and as part of our tour we visited Jericho--an oasis in the desert, filled with palm trees. You can see the perennial spring that supported the city for centuries and provided an irrigation system. Jericho was prepared for a siege.
Here's what God said to Joshua before He gave him the plan of attack: “I have delivered Jericho into your hands, along with its king and its fighting men” (2). Note the past tense: “I have delivered,” not “I will deliver.” God speaks of Jericho as having already been defeated. Joshua can proceed with confidence.
This was a most unusual attack. The account in chapter 6 reads more like a religious, ritual procession than forward lines of battle. And that's the point. Superior tactics and decisive military strategy don't win the battle here. Siege ramps and ladders are not constructed; they won't have to scale the wall. Neither does Israel intend to stave Jericho into surrender. James Boice notes: “From a human point of view, nothing could have been more useless. High walls do not fall to the noise of tramping feet; cities are not won by trumpets.” In the narrative there is a deliberate buildup to the climactic destruction of Jericho, and it is for our benefit. The battle belongs to the Lord, a one-sided affair. The defeat of Jericho is God's gift to Israel. The Lord of Hosts is Jericho's true attacker.