Old and about to “go the way of all earth” Joshua summarises very clearly what has happened for the people.
The Lord has kept his promise and given the land to them. He has no illusion that it is their military strength that has won the land: “one of you drives out a thousand because the Lord is on our side”. God has kept every promise.
They must stay true, and they will be blessed. Staying true means sticking to the law of moses, not associating with the Gods around them. Mixing, intermarrying, watering down their faith, will lose all that they have gained.
Its very clear, very clear.