On the day of judgement muslims believe that they will be judged for their action on Earth, those who followed Gods teachings will be rewarded with paradise and those who rejected Gods teachings will be punished with hell
Angels are important to muslims as they believe that angels will provide God with information of their deeds on judgement day
Muslims also believe that revelations to the prophets are provided by angels
Shirk - believing in multiple Gods or holding something or someone equal to God (seen as greatest sin in Islam)