Verse 6.— And the angels which kept not their first estate. Here, it is asserted as a fact, that heavenly messengers at some time in the past had sinned, deliberately left the habitation assigned them; and, although higher in many respects than man, God visited punishment upon them. They were cast out, and by him are reserved, bound as strongly as chains can bind, and kept under darkness until that great day which God has fixed, when their final doom will overwhelm them.