A week that atones for the entire year



They say there is a week that can atone for the whole year. As far as I know, this week is in Elul. I would like to know on what day this week begins!


The source for this is the Mishna Berura 603:2.

The Ya’arot Dvash Vol. 1 Drush 1 says that the 7 days between Rosh Hashana and Yomm Kippur correspond to the 7 weekdays and every day one should repent for all the sins that one did on that day. For example, on Sunday repent for the sins done on Sunday, etc.