I don't ever recall having a single specific discussion about "possession" here for the nearly dozen years I've posted here and generally avoid the topic because the space is filled with delusional believers and delusions of believers.
Anyone who is tempted internally and recognizes temptation IS of the tempter should be well able to do their own math on this matter. They should not find that to be 'possession' because it's NOT.
Part of the problem imho is that believers are so brainwashed by movies they instantly equate scriptural depictions of man and devil's very obvious overlap in the flesh as "possession." The vast majority of Jesus' encounters with devils in mankind were definitely not Hollywood style possession. It was every day encounters in everyday folk and in religious leaders, most of which didn't have a clue about how Jesus saw these matters of man/devils, which is far simpler. Internal theft, spiritual blindness, etc. Not possession. It's a captive/captor relationship that has many different "markings" as to what extent that might be. Mark 4:15 is a great example as is Acts 26:18, 2 Cor. 4:4, Eph. 2:2 etc.
The fact that believers sin and sin is directly connected to the devil is entirely open and obvious in 1 John 3:8. Paul's statement of fact in 2 Cor. 12:7 is more than ample similar scriptural evidence that "a messenger of Satan" did dwell in the flesh of an Apostle and temptation was also "in his flesh." Gal. 4:13-14. This is not a "hard dot" to connect, that messenger of Satan to "temptation." But sadly, readers just can't believe their eyes when they read it.
In regards to this thread, Jesus ALWAYS sought to "divide" devils from mankind OR, in the cases of religious people, He actually HARDENED those wicked spirits in those men and purposefully did NOT cast them out. John 8:44.
Romans 9 shows us that it is entirely Gods Call on how these matters are seen or not seen.
Romans 9:18
Therefore hath he mercy on whom he will have mercy, and whom he will he hardeneth.
Paul tells us also that the "majority"
will NOT see.
Romans 11:5
Even so then
at this present time also there is a remnant according to the election of grace.
If we have such an obvious matter in the scriptures, particularly of the N.T. scriptures, and "believers" still don't get it I really don't know what to say. The written evidence is beyond overwhelming, on nearly every page of the N.T. Gospels and so many warnings by the Apostles to us to NOT be slaves in the flesh to SIN and potentially demonic captives in the flesh it's well beyond missing.
The Sword of Gods Word is sharp. It is meant to divide PEOPLE from DEVILS. And this in most cases does not mean "cast out." That comes at the end, either of the flesh life of a believer or at the end of this wicked age.
1 John 5:19
And we know that we are of God, and
the whole world lieth in wickedness.
That wickedness is internal, evil present and sin dwelling in the flesh of man, no differently than it was in Paul, post salvation, in Romans 7:17:21.
Believers may not see it. But that's exactly where the battle ground is, in our own flesh.
2 Corinthians 7:1
Having therefore these promises, dearly beloved,
let us cleanse ourselves from all
filthiness of the flesh and
spirit, perfecting holiness in the fear of God.
Denial is not how that cleansing transpires. It is a TRIAL of FIRE. Rev. 3:18. And this has nothing to do with physical fire, but Spiritual Fire.