Tartarus, or the Abyss. Scripture speaks of a place where certain angelic beings are confined. It is called the "Abyss", signifying 'deep' or 'bottomless'. The Greek word used by Peter is Tartarus, meaning "deepest pit" (2 Peter 2:4). It is similar to Hades in that it is a temporary confinement, yet different in that no human can or will ever go there. It is a temporary holding place for fallen angels. The angels fell with Satan in his initial rebellion (Ezek. 28:14-15), and then a subset of them went a step further than the others; "the angels who sinned" (2 Pet. 2:4), who left "their own original state" (Jude 6), the "sons of God" who intermarried with humans before the flood (Gen. 6:2). Satan and his demons are free today to roam the earth and the heavenly places (Job 1:6-7), but the group that took wives of the daughters of men had their imprisonment expedited, and were cast "down to the deepest pit of gloom" and are "kept in eternal chains under gloomy darkness". Evidently, Satan and his demons know they will join the others at some "time" in the future; hence they begged Jesus not to send them there early (Luke 8:31; Matt. 8:29). Satan is somehow king of the Abyss (Rev. 9:11), though he is not banished there yet. When Christ appears, He will cast Satan into the Abyss for a thousand years (the "millennium", Rev. 20:1-3). Satan's demons too will also be cast into the pit for a thousand years, then "visited again" (Isa 24:21-23) when Satan is loosed. The fallen sons of God will not get out until the "great day" of judgment, when all the fallen angels will be cast into the Lake of Fire, their final destination (Matt. 25:41).