Ibn Abbaas (radiyallaahu-anhu) said about the statement of Allaah (The Mighty and Majestic) ”For each (person), there are Mu-aqqibaat in succession, before and behind him. They guard him by the Command of Allah.”  They are the angels that protect the person by the command of Allaah; but when what has been decreed for him arrives, they leave him.  [Jaami-ul Uloom Wal-Hikam: page: 199]