Devarim

The book of Devarim (Deuteronomy) contains Moshe's final words to the nation before they enter into the Land of Israel. Most of the book contains a review of the laws that they had already received from G-d until this point. Moshe begins by summarising their sojourns in the desert. He hints to the sins that the Jews had committed throughout their journey, by listing the place names where those sins occurred.
Moshe retells how he was unable to provide for the nation alone, and G-d commanded that he appoint leaders over the people, to provide judgement and leadership on a local level. He reminds the people of the sin of the spies, how they listened to the evil report that the spies brought back when they scouted out the Land of Israel and they refused to trust G-d and enter into it. Only Yehoshua bin Nun and Calev ben Yephuneh remained from that generation to enter into the land, because they remained firm in their faith.
The Israelites had wandered through the desert for another 38 years. Finally they journeyed towards the land of Se'ir, but the children of Esav refused to let them pass through their country. G-d also commanded that the Israelites not wage war on the Moavites, and they had to journey around their country also.
As the Jews approached the Land of Israel, Sichon and Og led out armies to battle against them. With the help of G-d the Israelites defeated them and conquered their lands. The tribes of Reuven and Gad asked to remain on the East side of the Jordan river and claim their inheritance there, where they saw there was good pasture land because they had large flocks and herds of animals. Moshe gave them this land on the condition that they enter with the other tribes into Israel and help them conquer the land before returning home to their families and their inheritance.