Did Paul believe in a place called "[the] abyss" that houses the [spirits] of the dead (Rom. 10:17)?
It seems very unlikely that anyone -- especially the apostles, were unfamiliar with the flames of Hades; this appears to be exactly what Romans 10:17 refers to:
Romans 10:17: “But the righteousness based on faith speaks as follows: ‘DO NOT SAY IN YOUR HEART, “WHO WILL ASCEND INTO HEAVEN?” (that is, to bring Christ down), or “WHO WILL DESCEND INTO THE ABYSS?” (that is, to bring Christ up from the dead)’” (cf. Deu. 30:13).
While the apostle is rhetorically admonishing the faithful not to ponder such questions as “Who will be saved and who will be lost?” Scripture appears to tip its hand to reveal that the spirits of the lost will “descend into the abyss.” As well, the parenthetical reference to Christ being raised “from the dead” also implies that the dead were once human, and are now spirits languishing in Hades, a chasm of horrors and prelude to Hell.
Most will agree that demons are Satan’s lieutenants, those that carry out his evil designs. During the first century A.D., these beings were fully capable of identifying themselves, and of communicating with the living (Mk. 5:7-12, cf. Acts 19:14-16). In the Gospel of Luke, we read of Christ encountering a demon-possessed man in the country of the Gerasenes. One of the passages reads as follows:
Luke 8:31: “[The demons] were imploring Him not to command them to go away into the abyss” (emphasis added).
Demons were highly perceptive; they immediately recognized the deity of Christ, and thus dared not disobey Him. Unfortunately, the same could not be said of unsuspecting human victims who fell prey to their devious manipulations. To those poor souls who were demon-possessed, the experience must have been horrific.
The term “abyss” is used frequently in the Book of Revelation (9:2, 11:7, 20:1) as the ultimate destination of those that oppose God and Man. What is interesting for this purpose is that, as demonstrated above, the same word, “abyss,” is used in Romans.
More than a few theologians believe that the most reasonable explanation for demons is that they are the spirits of fallen angels (cf. 2 Peter 4:2, Jude v. 6). While this stance seems plausible -- and is undeniably tempting, many believe that this view does not accurately reflect the biblical record.
References to "sons of God" in the O/T, while sometimes referring to angelic majesties (eg. Job 1:6, 2:1, 38:7, etc.), is speaking about godly lineages of people, not "fallen angels." Note that this same term is used throughout the N/T to refer to the faithful as well. The phrase "daughters of men" generally indicates the offspring of those who had no godly inclinations. The apostles would have understood the distinction without any reservations.
It seems that the spirits of the lost appear to be comprised of those who were at one time human, those uncleansed by the Blood of Christ. Angels are ministering spirits; they serve the will of God (Genesis 18:2, 19:1, esp. Heb. 1:14). These heavenly creatures possess no sexual component. Only a purely carnal perspective of these celestial majesties could possibly believe otherwise:
Matthew 22:30: "For in the resurrection [the saved] neither marry nor are given in marriage, but are like angels in heaven."
This is the only interpretation that makes sense. Further, angels have absolutely no desire to inhabit the lives of others; they are otherwise purely spiritual beings. None of the apostles including Paul could possibly have been unaware of this fact.
Demons, on the other hand, are always seeking to commandeer living human hosts:
Luke 11:24-26: “When the unclean spirit goes out of a man, it passes through waterless places seeking rest, and not finding any, it says, ‘I will return to my house [human host] from which I came.’ And when it comes, it finds it swept and put in order. Then it goes and takes along seven other spirits more evil than itself, and they go in and live there; and the last state of that man becomes worse than the first.”
Demons would like nothing more than to possess human beings at every turn, given the opportunity. Why? Because inhabiting a human being -- indeed, inhabiting unclean animals like pigs, is preferable to the torment of the abyss: Hades.
In the Gospel of Mark (5:12-13), unclean spirits that possessed one (of two) man implored Christ that they be allowed to enter into a herd of nearby swine, animals considered unclean under the Law of Moses.
Demons are portrayed as emerging from the underworld or dust of the earth: the dwelling place of the dead. A passage from the Book of Isaiah reveals a glimpse of this:
Isaiah 29:4: “Then you will be brought low; From the earth you will speak, And from the dust where you are prostrate Your words will come. Your voice will also be like that of a spirit from the ground, And your speech will whisper from the dust.”
In the Gospel of Matthew, we read of Christ’s final message, first to the saved:
Matthew 25:34: “Then the King will say to those on His right, ‘Come, you who are blessed of My Father, inherit the kingdom prepared for you from the foundation of the world.’"
However, the next passages refer to those who are lost eternally:
Matthew 25:41: "Then He will also say to those on His left, ‘Depart from Me, accursed ones, into the eternal fire which has been prepared for the devil and his angels.’”
The “accursed ones” and "the devil and his angels [messengers]" in the latter passage are denounced for their absence of compassion. Nonetheless, since all of the earlier passages of Matthew 25 contrast human beings (angels appear nowhere) who were prepared (Parable of the Ten Virgins), faithful and obedient (Parable of the Talents), with those unprepared, unfaithful and disobedient, it can hardly be argued that the “accursed ones” were not human beings. They were those who would be cast into the eternal fire “prepared for the Devil and his angels.”
Here, let us observe a passage from John's Gospel as Christ is speaking to a hostile, faithless audience. Note the strong language He uses to describe them:
John 8:44: “You are of your father the devil, and you want to do the desires of your father. He was a murderer from the beginning, and does not stand in the truth because there is no truth in him."
Just what, precisely, is the distinction between "the Devil and his angels [messengers]" (Matt. 25:41) and "children of the Devil" (Jn. 8:44)? Only this: the first group has no chance whatsoever, while the second may receive the eternal gift offered by Christ.
It appears that if the Son of God characterizes lost human spirits in this manner, then it is rather difficult to escape the conclusion that fundamentally, those outside the blood of Christ have become unclean spirits or demons.
Indeed, Paul and the apostles believed that "the abyss" constrained the spirits of the lost dead, which will eventually be cast into the Lake of Fire.