If angels could sin, then the righteous would also be able to sin and therefore would have the possibility of dying, which means they would not really have everlasting life.
Ikiwa Malaika waweza kutenda dhambi, ndipo na wenye haki nao wataweza kufanya dhambi na kwa hiyo watakuwa na uwezekano wa kufa, ina maana kwa kweli hawatakuwa na uzima wa milele.