Joshua picks up exactly where Moses left off, and exactly where the last chapter of Deuteronomy left us. Moses has died and God informs Joshua that he’s now the head of this nation that’s about to claim the land they’ve been promised.
If I were to sum up this chapter it’s “have courage.” Multiple times Joshua is told to be strong and have courage. This job he’s inherited will be difficult and many times thankless, but he’s been called to it and must play his part.
He gathers up the people and starts to prepare them to cross over the Jordan and take possession of the land. This crossing is also allegorical for us in that it’s a prefigurement of baptism. Just like the waters of baptism were represented by the flood and Noah, and Moses in the Red Sea, so too does the Jordan and crossing into the land representing our Christian life on earth. Where instead of driving out heathen nations, we’re to drive out old habits and stumbling blocks that will get between us and God. (See Living out our baptism for more on this theme)
Before the invasion begins, Joshua send in spies to find weak points in the defenses of Jericho, just like he was sent as a spy some 40 years earlier. But this time they’re discovered and have to hide in the house of a harlot.
She hides them and secures a promise of safety from them if she helps them escape. They agree and give her a sign to hang from her window, a red thread and the Israelites will not harm anyone inside. Maybe they were inspired by the red blood of the lambs from Passover but wanted to be less noticeable.
With the signal agreed to, they escape over the wall and return to Joshua who is gladdened by the news that the inhabitants of the land already fear them. Physiological warfare is nothing new, and it helps defeat the enemy even back then.