I'm sorry Jim, but you have fallen for one of the most pernicious false doctrines, one that has been consistently and endlessly taught throughout the body of Christ to its great detriment.
And the reason you can't back it from scripture is that it is completely unscriptural!
It is pernicious on several counts, the primary one being that it leaves Christians completely defenceless and vulnerable to very real demonic attack.
And yes, I can back it up from scripture that demons can, and regularly do, enter and indwell in the same place where the Spirit of God indwells.-
That fact is demonstrated in Ezekiel by the demon inspired pagan idols placed by the Jewish leaders inside the temple of the Lord in Jerusalem, right where the Spirit of the Lord dwelt.
This parallels the indwelling of the Holy Spirit in the temple of our physical bodies.
Yes, the Holy Spirit eventually departed, but that happened long after they put their idols in the temple.
To understand the whole story in context you need to read Ezekiel 8 through to 11, but here are some extracts.
For reference, Ezekiel was one of the early captives taken to Babylon by Nebuchadnezzar. In these passages the Lord takes him in vision back to Jerusalem to see how detestable the idolatry had become in its take over of the temple. (And we know from 1Cor 10v20 that behind every pagan idol is a resident demon masquerading as one of the various gods.)
Ezekiel 8v3He stretched out what looked like a hand and took me by the hair of my head. The Spirit lifted me up between earth and heaven and in visions of God he took me to Jerusalem, to the entrance of the north gate of the inner court, where the idol that provokes to jealousy stood. 4And there before me was the glory of the God of Israel, as in the vision I had seen in the plain.
The
Glory of the God of Israel identifies that the Spirit of the Lord was very much in residence there, and Ezekiel is shown the first idol, also in residence there.
5Then he said to me, “Son of man, look toward the north.” So I looked, and in the entrance north of the gate of the altar I saw this idol of jealousy.
6And he said to me, “Son of man, do you see what they are doing—the utterly detestable things the Israelites are doing here, things that will drive me far from my sanctuary? But you will see things that are even more detestable.”
Take note the future tense of the Lord departing the temple!
The Lord then commands him in the vision to dig a hole in the wall and see what else was going on inside.-
8v10So I went in and looked, and I saw portrayed all over the walls all kinds of crawling things and unclean animals and all the idols of Israel. 11In front of them stood seventy elders of Israel, and Jaazaniah son of Shaphan was standing among them. Each had a censer in his hand, and a fragrant cloud of incense was rising.
The Lord takes him further.-
8v14Then he brought me to the entrance of the north gate of the house of the Lord, and I saw women sitting there, mourning the god Tammuz. (Tammuz was one of the main Babylonian gods.)
The Lord's tour around the paganised temple goes on through chapters 9, 10 &11 until the Lord takes his leave of the temple.
Moving on from Ezekiel.
I am showing this because it shows Satan approaching the Lord wherever his throne was.
Job1v6One day the angels came to present themselves before the Lord, and Satan also came with them. 7The Lord said to Satan, “Where have you come from?”
You can read the rest of that dialogue in Job, but again it makes a nonsense of the idea that Satan cannot be anywhere God dwells.
You are right here in that we have free choices to do evil, but invariably when we follow our flesh and make evil choices, that decision opens the door and lays out a welcome mat for the entry of demons.