The sixth aliyah discusses tzoraas that afflicts houses. A house that contracts terminal tzoraas is to be broken down. In passuk 34 G-d says that when the Jews will get to the land of Canaan, G-d will give their houses the disease of Tzoraas. This is an example of the Jewish principle that whatever G-d does, is good. Here the Jews are told that, in Israel, their houses will contract tzoraas, and as a result will have to be broken down. But Rashi explains that during the 40 years the Jews are in the desert, the Amorite nation in Canaan hid their golden treasures in the walls of their houses. When the Jews took possession of those houses after entering the land, the houses contracted tzoraas, and when the Jews broke down the walls, they found the treasures.