A man named Achan had disobeyed God’s commandment to not take spoil from Jericho. Subsequently, Israel suffered a surprising defeat at Ai, their invasion after Jericho, because this sin was not addressed.
The day has come for the first battle in the Land. God gave Joshua the strategy, and victory through Divine assistance. The army marched and the walls fell at the trumpet’s blasts. Also, Rahab and family were saved.
Another basic mistake made by many sincere “Christians” is that in their effort to reach people with the gospel, they ignore God’s truths. Some actually suppose that peace is more desirable than purity, wrong!
Joshua makes the armies of the Lord ready for the conquest of Jericho, then the rest of the Land. To do this he must comply with a neglected rite of the Hebrews, after which he is granted a visit from the Lord Himself.