Question: Hi, I've just found your site, may God bless you for your ministry. Could you tell me the difference, if any, between fallen angels, demons, evil spirits, spiritual forces of wickedness, etc. Most people seem to assume that they are all one in the same. I'm not sure I see it that way as both Peter and Jude seem to assert that fallen angels have been long ago bound, and I assume that by "long ago" they mean before their lifetimes and we can be sure that during their lifetimes demons seemed to abound. But if demons aren't fallen angels then where did they come from? Thank you
Response: Thanks for your encouragement. As to your question about Satan's forces, I have written fairly extensively about this and will give you the links below. Let me say by way of overview though that the one thing that all of these categories have in common (i.e., fallen angels, demons, evil spirits, spiritual forces of wickedness, etc.) is that they are all angels, and, specifically, angels who chose to follow Satan in rebellion against God before the creation of mankind (the Satanic Rebellion series explains all this in some detail). That is the similarity. The differences between various fallen angels (which accounts for the varying terminology in scripture) are essentially twofold:
1) fallen angels differ in rank (that is the thrust of Paul's discussion in Ephesians 6:12; cf. also Rom.8:38).
2) fallen angels differ in their locales: some of them are indeed not presently at liberty (e.g., all those involved in the activities described in Genesis chapter six are currently incarcerated in Tartarus: the Peter and Jude passages you mention speak of these).
3) fallen angels differ in their activities: some are indeed active in possession (cf. the "legion" which possessed the Gaderene demoniac), but others are focused on observing and opposing believers (cf. 1Pet.5:8 where we may be sure that the devil, who cannot be in more than one place at a time, is delegating this activity).
There is much we do not know about the organization and nomenclature of the devil's forces, but they are all "angels" (of various rank, in various locations, involved in various activities). Here are some links to more extensive discussions of this subject:
The order of battle of the fallen angels (from SR#4).
Satan's Tactics (from Peter #26)
Satan's antediluvian attack on the purity of the human line (the Nephilim) (from SR#5)
As I say, the entire Satanic Rebellion series will be helpful in this regard. Hope this helps to answer your question, and you can also consult the Subject Index at Ichthys for particular topics.
In our Lord Jesus Christ.