Daniel 10:12 is a strange and difficult passage. First of all we need to identify the "players". They are
Prince of Persia
Second of all we need to identify what’s happening. Daniel made a prayer for his people. The speakers (an angel) heard the prayer or was "commissioned" to act upon it. Somehow, the prince of Persia was critical to how Daniel’s people were in their persecution/plight and had to be persuaded to change. The angel (the Speaker) could not accomplish this task and was "tied-up" for 21-days until the Archangel Michael became involved, to successfully "persuade" the prince of Persia .
I don't think the "prince of Persia" is any sort of human governor, prince, king, etc. In fact, I think the prince of Persia is some sort of fallen or evil angel - for all intent and purposes, a demon. This demon-prince of Persia does not rule in a political sense, but rules and effects (affects?) the minds of Persia's human rulers. Now this will inevitably lead us back to hell (or in this case, Hell). Does Satan and his fallen angels and/or demons reside in Hell? Not yet, as it only come into existence at the End Times. Extremely few today would honestly say they believe in a Hell with a physical, geographical location. The point I'm getting to is that we are completely dealing with the Spiritual Realm, or the "Heavenly Realms".
We have the issue of an angel being "detained" for 21-days. This is making the assumption that the "heavenly realms" are eternal which I don’t believe the bible supports.
Genesis 1:1 clearly states that "In the beginning God created the heavens and the earth" thus making "the heavens" a created thing. Now it could be debated whether this was meant to mean the sky and heavens as in space and outer space, but Genesis 1:16 clearly makes this distinction, specifying the sun, the moon, and stars. So, Genesis 1:16 is not talking about the "heavenly" or spiritual realms. Also, Genesis 1:6-8 refers to "the waters" of the earth (the raw materials of the universe) being divided and organized. The earth is formed (the physical universe) and the heavens are also created (the spiritual universe) during this "parting of the waters/filaments".
Revelations 21:1 and Isaiah 65:17 speak of a new heaven and earth. The Greek word used for new is καινός (kainos), which does not mean "new" in a chronological sense, but "new" as to be fresh or refreshed – like hitting the refresh button on your internet explorer’s toolbar – what was previously there is simply gone, overwritten.
So we can safely say that these "heavenly realms" have a definite beginning (Gen. 1:6-8) and also a definite end (Rev. 21:1). This "heaven" exists within the context of history. It is a temporal thing (which Daniel 10:12 also confirms).
Now, many assume that this "heavenly realm" is the Heaven we like to teach our young children about (We’ll have to make some sort of distinction here, so I’ll refer to this heaven with a capital “H”) – a place of clouds, pearly gates, good angels, Saints, and where God "lives". (Hell, being somewhere else). This assumption is wrong.
Ephesians 6:12 confirms that there are spiritual forces of evil in the heavenly realms. Thus the "heavenly realms" are not a Holy and Good place. It is not where God the Father "resides". These "heavenly realms" are part of the Created Universe and God the Father "resides" somewhere "outside" of Creation (in His truly eternal state). This is not "Heaven" where we go when we die (that Heaven – eternal life – is only after the End Times), but would most definitely be more correctly called a "spiritual realm".
So it is very conceivable for an angel to be detained for 21-days in either our physical world or the spiritual world. Both these compose our Created Universe and both are subjected to time.
However, bearing in mind that this is all a dream or a kind of vision to Daniel, all these "truths" and revelations could well be put into a context, or use imagery that a very human Daniel can comprehend. So, there could be strong symbolism used here too.
I believe these passages
spell out that the "spiritual realms" (heavenly realms) are very much bound by time (they are not eternal) and are neither Heaven nor Hell.
Also, if we apply the Kalam Argument we find the same results. The Kalam Argument makes 3 simple statements:
1) If something had a beginning it had a cause
2) The universe had a beginning
3) The universe was caused.
If we use the inverse argument we’ll discover that only something that is eternal has no cause and no beginning. Since these "heavenly realms" has both a cause and a beginning they cannot be eternal. If they are not eternal then they are bound by time.
Conclusion: The “Heavenly Realms” are not Heaven proper, but an active Spiritual Realm where both good and evil are active. When Job 1:6-12 and Job 2:1-7 speak of Satan sitting in the presence of God and His angels also ties into and confirms this conclusion: the “heavenly realms” are really a time-bound aspect of our Created Universe – a spiritual realm, and possibly Sheol.
So we are left with the question, What does happen to us when we die? I believe the answer to that question lies with Sheol. Is this “heavenly”/spiritual realm Sheol?
Sheol, Soul-Sleep, & Purgatory
Often Sheol is freely translated into Hell and Hades. Although Hades is Greek and Sheol is Hebrew, ultimately, beyond the language issue, I don’t believe they are the same thing as “Hell”. The translators of the King James Version translate the name Sheol into “hell” 31 times, “the grave” 31 times and “the pit” 3 times. These translations are in error, most especially “hell”. Sheol is the common fate of all mortals. It is not a place of punishment. In Psalm 16:9-11 the author acknowledges that he will not be left in “hell” after death but that God will show him the path to life. The use of the word “hell” should actually have been left as the original Sheol for they do not suggest the same thing.
The Hebrew word Sheol (or sheh-ole) means Hades or the world of the dead, as in a subterranean retreat – the grave. However, when the word Sheol got translated into the Greek Hades in inevitably introduced various Pagan-Greek beliefs and assumptions about the nature of Hades. In Greek Mythology, Hades was not only the place of the dead, but more closely resembles, in its nature, the traditionalist’s Hell. The Hebrew’s Sheol is none of these things. There are ample passages from both the Old Testament and New Testament (as well as from Intertestamental writings) that refer to the dead sleeping or being in some sort of state of hibernation – but not punishment and suffering. The dead do not ascend to Heaven nor or descend Hell. The dead go down into “sleep”. There are many and various passages that state this. To cite a few for example from the Old Testament there are Jeremiah 51:39, Job 14:12, Psalms 17:15, Daniel 12:2, 1 Samuel 28:11-20.
From the New Testament there are Acts 7:60, Acts 13:36, 1 Corinthians 15:6, 1 Corinthians 15:18, 1 Corinthians 15:51, 1 Thess. 4:13-15, and 2 Peter 3:4.
From the Inter-testament writings we have Tobit 14:6-8 and 2 Maccabees 12:43-45. However, 2 Maccabees 12:43-45 is an interesting passage:
“He also took up a collection, man by man, to the amount of two thousand drachmas of silver, and sent it to Jerusalem to provide for a sin offering. In doing this he acted very well and honorably, taking account of the resurrection. For if he were not expecting that those who had fallen would rise again, it would have been superfluous and foolish to pray for the dead. But if he was looking to the splendid reward that is laid up for those who fall asleep in godliness, it was a holy and pious thought. Therefore he made atonement for the dead, that they might be delivered from their sin.”2 Maccabees 12:43-45 (RSV)
2 Maccabees 12:43-45 does more than just confirm (with the addition of other passages) that the dead are in some sort of soul-sleep or spiritual hibernation. It also strongly suggests that even after death (and before the End Times) that there is still hope for salvation. It suggests that those who have died “unsaved” still have a chance for salvation.
Now - and we must be careful here - it implies these things but does not directly state nor teach it. However, having said that, this passage does introduce the possibility of some sort of Purgatory, or the potential of Sheol actually being Purgatory, a place or state of possible purification. So the question must be asked, do the “unsaved” dead have any hope for salvation? 2 Macc. 12:43-45 definitely confirms “soul-sleep” and possibly some sort of purgatory. However, if Jesus taught that the opportunity to repent was cut off at death then this isn’t a possible interpretation.
Are the Spiritual Realms (a place of activity) and Sheol (a place of the dead and inactivity) the same? No, there is no scriptural indication or reason to believe so. Sheol is a place of waiting and rest, a place of “soul-sleep” or spiritual hibernation. So the “spiritual realms” (or “heavenly realms”) are not Sheol. But is Sheol and Purgatory the same? Does Jesus teach that the voluntary opportunity to repent is cut off at death? Does He teach that an external intervention after death is impossible – a posthumous intervention towards salvation?
The Sleep of Sheol vs. Direct Bodily Ascension
If the dead go down into the sleep of Sheol, then how can we explain those figures that directly bodily ascended to Heaven? How do we explain Enoch (Gen. 5:24), Elijah (2 Kings 2:11), and Jesus?
In 1 Samuel 28:11-20, Samuel was “called up” from his “sleep” in Sheol by the Witch of Endor; confirming both Sheol and “soul-sleep”.
However, in the Transfiguration (Mat. 17:1-8, Mark 9:2-8, & Luke 9:28-36) both Moses and Elijah were present which seems to be a contradiction. Elijah did not go down into “the sleep of Sheol”, but was ascended directly and bodily into Heaven. How could he have been present at the Transfiguration? We know that the dead may be “called up” from their “sleep in Sheol” from 1 Samuel 28:11-20. But can someone who was directly ascended into Heaven (not the “heavenly realms) be “called up” or “summoned”?
In the Transfiguration if both Moses and Elijah were called up from the dead (which is the common interpretation), what could Jesus be talking to them about? If Moses was called up from Sheol (a place of no activity, no interaction – of rest, waiting, and sleep) what could possibly be the point of a conversation? Jesus – especially in His Transfiguration, (which I feel is more closely approaching that state of the Divine Logos ) is “shedding” His self-imposed limitedness, has absolutely nothing to gain or learn from Moses. In fact, the conversation’s only purpose could be for revelation to Moses. But again, revelation for what purpose considering where Moses was “summoned” from and returning to.
If Elijah was called from Heaven (or his “eternal life”, not Sheol) then he has effectively seen the “other” side of eternity. What possible good could revelation be to him?
This interpretation of the Transfiguration becomes riddled with problems. The assumption in the interpretation is a chronological one. It is assumed that on the mountaintop Jesus encountered both Moses (who has been long since dead) and Elijah (who has also been long since dead) and that both of them somehow were called up. Scripture tells us very little about what they talked about. It is only in Luke 9:31which mention anything of the topic matter. “…and spoke of his decease which he should accomplish at Jerusalem.” (KJV)
“His Decease” – literally, his “exit” or “departure”. The word translated here “decease” – that is, exit, or “going out” – is elsewhere used to denote death. See 2 Peter 1:15. Death is a departure or going out from this life. In "this" word there may be an allusion to the “departure” of the children of Israel from Egypt. As that was going out from “bondage,” pain, and humiliation, so death, to a saint, is but going forth from a land of captivity and thralldom to one of plenty and freedom; to the land of promise, the Canaan in the skies.Barnes Notes
Is it possible that the Transfiguration was something else entirely?
In Exodus 24:15-18 it talks about Moses on the mount and the mount being covered with a cloud and the cloud covering it for 6 days and on the 7th day the Lord spoke to Moses. The sight of the glory of the Lord was like devouring fire. Moses was on the mount for 40 days and 40 nights. There is also mention in Exodus 34:29 that Moses’ face shone as the sun, with a special brightness.
In 1 Kings 19:8 Elijah went to Mount Horeb for 40 days and 40 nights (similar to the amount of time Moses was on the mount), and the word of the Lord came to him.
The Synoptic Gospels accounts of the Transfiguration (Matthew 17:1-8, Mark 9:2-8, & Luke 9:28-36) say that after 6 days (which is the same amount of time Moses was forced to wait before God spoke to him) Jesus brought Peter, James, and John up to a high mountain and was transfigured before them and that His face shone like the sun and His clothes were like light, and He was talking to Moses and Elijah. And as they talked a bright cloud overshadowed them.
Could these three incidents have actually occurred "outside" of time and simultaneously, within both Moses’ and Elijah’s lifetimes? What was Jesus talking about to Moses and Elijah? We know He was talking about His death and an achievement in Jerusalem. This can only mean his Crucifixion and ultimately the vicarious atonement – Salvation. But could there have been more? Could the actual conversations be recorded in Exodus 24:15-18 and 1 Kings 19:8? Could these three events have actually been only one event? Could it have been Jesus - in His Transfigured state - that spoke to Moses on the mount? Could it have been that it was a Transfigured Jesus who spoke to Elijah in the cave on Mount Horeb?
The common assumption is that Jesus is talking to a posthumous Moses and Elijah. We do not know this to be true we only assume it.