Bless, Father.
Thanks for sharing your knowledge with us. I have another question that may tie into Achronos' OP: is it really possible for a practicing Christian to become possessed by a demon or demons? I don't presently have time to search patristics or Scripture, but I recall several Scriptural passages stating something to the effect that a Christian can be influenced/persuaded by demons, but cannot be possessed. What do you think? What is your experience?
Actually, all y'all are free to lend your thoughts. If you have Patristic or Scriptural quotes, please include them. Thanks!

Excellent question Gabriel. I too await to hear what some of our Priests have to say on the matter. My own opinion is that it is not possible for a practicing Christian to become demonically possessed. I do not think it is possible for the Holy Spirit to dwell alongside demons within an individual. St. Paul asks,
“What fellowship has righteousness with lawlessness? And what communion has light with darkness? And what accord has Christ with Belial? And what agreement has the temple of God with idols? For you are the temple of the living God. As God has said, ‘I will dwell in them and walk among them. I will be their God and they shall be my people.’ Therefore, Come out from among them and be separate, says the Lord. Do not touch what is unclean, and I will receive you.”” [II Corinthians 6:14-18]
I think you are correct in your speculation that practicing Christians can be oppressed, influenced, tormented, and persecuted by demonic forces, but not actually possessed. Job was severely tortured by satan himself, but satan could never enter his heart, mind, or soul. Apparently the devil was able to exert some type of external physical harm upon Job, but nevertheless he could not deter the righteous man from loving and praising God. “Though He slay me, yet will I trust in Him.” [Job 13:15]
But the key word here is “practicing” Christian. By grace it is possible for our free will to elevate us to theosis, but we can also use our free will to apostasize and become pawns of the devil. St. Anthony is a glorious example of a man who by use of his divinely guided free will attained theosis and averted every demonic arrow hurled his way. I often think that St. Anthony must have frequently meditated upon the life of Job during his time on earth. Yet others have chosen to forsake Christ and deny Orthodox Truth little by little until their hearts are eventually hardened and they are no longer receptive to the Holy Spirit. They therefore open their souls to satan, and possession becomes a very real possibility.
Now, these are only my own humble opinions. I certainly am not a Priest, and I do look forward to learning what our Priests on this forum have to teach us regarding this important issue.
Selam