It seems to me that the purpose of the people taking time to overview their history was two- fold. The passage speaks of exalting God in verses 5 and 6. It brings attention to the attributes of God as promise keeper (vs 8), covenant keeper (vs. 32), as just and faithful (vs 11,12,13,15,20,21, 24, 33), as compassionate and kind (vs 9,17,19). All this to bring God glory. There also seems to be an element that is for the purpose of acknowledging their sin and repenting of it.