Two separate identities, the Angel of the Lord and the Lord of Hosts are identified here. The Angel asks a question of time frame, how long. In a sense the mercy has not left, it is there all along. In another sense on the ground the appearance is one of His displeasure; which itself ties back into His mercy. It would not be mercy if He had not had a plan/means of dealing with it.
2012 - pBiblx2 Field Wise Bible System Version 2.0.9d - GPL3