After the evil has been removed from Israel, the people get a new opportunity to conquer Ai. God prescribes exactly how they should proceed. Only if they listen to Him will they overcome. An ambush must be laid. The enemy does not count on that. From this ambush the city is taken.
So also now every believer has a source of power that is invisible to the world. This source of power is the Holy Spirit. The world does not see Him or know Him, as the Lord Jesus says: “The Spirit of truth, whom the world cannot receive, because it does not see Him or know Him, [but] you know Him because He abides with you and will be in you” (Jn 14:1717[that is] the Spirit of truth, whom the world cannot receive, because it does not see Him or know Him, [but] you know Him because He abides with you and will be in you.).
When victory is achieved, Joshua builds an altar. The offerings that are brought thereon speak of the Lord Jesus (Heb 10:5-105Therefore, when He comes into the world, He says, “Sacrifice and offering You have not desired, But a body You have prepared for Me;6In whole burnt offerings and [sacrifices] for sin You have taken no pleasure.7“Then I said, ‘Behold, I have come (In the scroll of the book it is written of Me) To do Your will, O God.’”8After saying above, “Sacrifices and offerings and whole burnt offerings and [sacrifices] for sin You have not desired, nor have You taken pleasure [in them]” (which are offered according to the Law),9then He said, “Behold, I have come to do Your will.” He takes away the first in order to establish the second.10By this will we have been sanctified through the offering of the body of Jesus Christ once for all.). Every victory we achieve is only due to what the Lord Jesus did on the cross.
The reading of the law at the end of this chapter indicates that obedience to the Word of God is the only guarantee for every victory and every altar.
Joshua 7-8 teach us an important spiritual lesson: the judgment of ourselves precedes the judgment of our enemies. “The sword of the Spirit, which is the word of God” (Eph 6:17b17And take the helmet of salvation, and the sword of the Spirit, which is the word of God.) must first do its sanctifying work in our lives before we can apply it to the lives of others.
Joshua 8 teaches us the return of Israel to the power of God. For their restoration they have to perform a lot of actions. All this would not have been necessary if they had acted in simplicity and sincerity of faith. But God uses these things to teach us who we are and who He is. Pride and false confidence receive a serious lesson here. It takes more effort to return in the way of blessing than it would have cost to avoid evil.
From Joshua 10:28 and onward the cities are conquered in mass. The conquests of Jericho (Joshua 6), Ai (Joshua 8) and Gibeon (Joshua 10) give the necessary principles of conquest that apply to all cities that they have to conquer afterwards. We must see what these cities represent in our lives and how we can overcome them. If we gain a victory in the power of God, then there is a danger that we will trust in our own strength. Ai teaches us how weak we are. In the picture of the chain that is as strong as the weakest link, we are as strong as the weakest Christian among us (Achan). Gibeon (Joshua 9) teaches us that the enemy is cunning.