Why Are Cedar Wood Crimson Thread and Hyssop Used for a House with Tzaraas

3) The Terumas HaDeshen quotes Rashi (Vayikra 14:34), who writes that the previous Canaanite inhabitants hid their treasures in the walls of their homes. When a house was afflicted with tzara’as, the process of scraping the house would reveal these valuable items. Because wealth can make a person arrogant, Hashem required the use of cedar wood, crimson thread, and hyssop to warn the person in advance of the need to remain humble. (R’ Ozer Alport)