Malbim: Since it was not a full Ge'ulah, and the prior sins were not totally cleansed, this Ge'ulah was so we will fix our ways and cleanse the sins. So the angel revealed to Daniel "Shavu'im Shiv'im Nechtach Al Amecha Lechalei ha'Pesha u'Lechaper Avon." We are doing the opposite - we added new sins!