Here is what Jesus said, and the context:
22Then was brought unto him one possessed with a devil, blind, and dumb: and he healed him, insomuch that the blind and dumb both spake and saw.
23And all the people were amazed, and said, Is not this the son of David?
24But when the Pharisees heard it, they said, This fellow doth not cast out devils, but by Beelzebub the prince of the devils.
25And Jesus knew their thoughts, and said unto them, Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand:
26And if Satan cast out Satan, he is divided against himself; how shall then his kingdom stand?
27And if I by Beelzebub cast out devils, by whom do your children cast them out? therefore they shall be your judges.
28But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you.
Notice, howeve, Jesus did NOT say that Satan never casts out Satan, or demons do not cast out demons.
Consider. Other, non-Cchristian, or ever Jewish, religions practice rites of exorcism. Do they work? I don't know, but let's assume that as they have been conducted 100s or 1000s of years that sometimes they do.
Then, by definition, Satan is casting out Satan, as we know that God isn't doing it.
Notice also what Jesus said, “Every kingdom divided against itself is brought to desolation; and every city or house divided against itself shall not stand”.
OK, we know, because the bible tells us so, that Satan's house will be brought to desolation in the fullness of time. Also, we know, just from observation that to follow Satan is to be self-centered and selfish. You would assume that it would be the same for demons as for humans. Therefore, one would hardly hesitate to stab another in the back if it gained him an advantage.
Further, look at, say, an system of evil such as socialism. Look at the many varieties of it historically, and how the followers of these systems have killed each other with a ferocity that they can hardly match with their killings of capitalists. The Nazis and the Soviets, for example.
Is this not, figuratively, Satan casting out Satan?
I'm not saying that I'm correct in this analysis: I'm hardly an expert. But I think that giving the wording, at least in King James English, the possibility is open for this interpretation.
"Even him, whose coming is after Satan with all power and signs and lying wonders. And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved." 2 Thess. 2:8,9.
MATTHEW 12:28"But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you.
Notice, howeve, Jesus did NOT say that Satan never casts out Satan, or demons do not cast out demons."
Study of scripture shows there is a fool proof way. How would you know for sure? Well there is a clear cut guide in the bible which Catholics and Protestant use.
I have been reading About exorcists or deliverance from books and articles for years. I have even meet the enemy through a friend's wife. She is into spellcasting.
The basic common link is this:
1 John 4 (New International Version)
1 John 4
On Denying the Incarnation
1" Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. 2 This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, 3 but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world."
At the end of each exorcism the victim has to declare in the personal pronoun that he or she believes Jesus Christ came in the flesh Meaning divinity became human. If the victim does not do this they know the exorcism is not over till this is done. I have read Catholic or Protestant do the same. So this is the real common link to know that person is fully deliver.
Now my personal experience I went to help a friend move. His wife who is into this new age crap likes to do spellcasting and tarot cards. She tried to "read" me without my permission I claim the Blood of Christ over this thus she could not "read" me. Also she then says at least I am a Christian.
Well I told her she is no christian. Guess how I prove it. I told her to recite and mean it the apostle's creed she could not do it. When it came to born of the virgin Mary =which equals flesh or became human. Several times could not say. Nothing but a lot of facial contortions and stutterings. Then told her to declare out right that Christ came in the flesh born of a woman. She would try then say out of desperation that there are many Gods with same contortions. Her husband was horrorfied. To make a long story short she is still a work in progress. I gave the husband a blessed exorcism medal and exorcism blessed cloth. She did not know what it was until he silently showed her. He never told her what it was. She fell down.
Anyway 1john 4 is the rule if it is not the rule the bible would be useless. But we can stand on it. Praise Jesus!