One is forbidden to eat or drink, bathe, use moisturizing creams or oils, wear leather shoes or have marital relations. The idea is to minimize pleasure and to let the body feel the distress the soul should feel over these tragedies. We also say Kinot, special poems recounting the tragedies that have befallen the Jewish people. Moshe reviews the history of the 40 years of wandering the desert and gives rebuke so that the Jewish people will learn from their mistakes. It is always good to give reproof right before one dies.
People are more inclined to pay attention.
Moshe recalls what happened at Mt. Sinai, the appointment of judges and administrators, the story of the spies, the prohibition to attack Edom and Moav, the defeat of the Kings Sichon and Og, and how the land of Gilad was given to the tribes of Reuven, Gad and half of the tribe of Menashe. He took us out of Egypt to hand us over to Amorites to destroy us. Rashi, the great commentator, elucidates this verse and gives us a profound insight into human nature. Says Rashi, that the Almighty really loved the Israelites, but because they felt hatred towards Him, they mistakenly felt that He hated them. There is a strong tendency for people to project their own feelings towards others.