Jesus' response is basically that a house divided against itself can not stand, implying that Satan would not undo his own work in order to make people think he's good.
In order to toss out demons, the exorcist must be more powerful than the one controlling the demons:
How in the world do you think it's possible in broad daylight to enter the house of an awake, able-bodied man and walk off with his possessions unless you tie him up first?Many in my church culture see the "holy roller" activity, speaking in tongues, casting out of demons, etc, of some church groups and denounce it as "christian in name only but actually of the devil". However, if -- and you'll notice that "if" is italicized -- if people actually change during these exorcisms from alcoholics to former alcoholics, or from wife-beaters into wife-nurturers, or from asthmatics to free-breathers, has not the strong man been tied up?
I have seen a few indications that at least some of these "healings" actually take place. I've seen many other indications that some of these "healings" are emotionally-driven through psychosomatic mechanisms. (I've never seen evidence of a physical healing, such as the sudden eradication of cancer, or the replacement of a missing limb, or the reversal of aging, etc. I'm not saying it's never happened, but I'm highly suspicious.)
The point is, even if it's a psychosomatic healing, has not the strong man been tied up?
And if the strong man has been tied up, who are we to declare this activity to be of the devil?
That seems to me to have been Jesus' point.
It scares me that so many in my church brotherhood "know" all the answers, and judge outsiders as being stubborn or intellectually lazy or lacking a love of the Truth. "We" have the Truth because "we" love the Truth; other religious groups are lost and going to hell because they don't love the Truth enough to think and believe like "we" do.
And yet Jesus says to look at their fruit - are those groups nicer than "we" are? Are they more God-minded than "we"? Do they do more to eradicate poverty and drug-use in society than "we" do?
Suffice it to say that I would hate to be judged by my brethren on that Great Day -- I'm neither good enough nor doctrinally pure enough in their eyes to pass muster. And part of that is apparently because I don't "love the Truth" enough to have found it as they've found it. (And that's true -- I've just this past year seen a darkness in my deepest parts that I wasn't really aware of -- I'm not the Truth Seeker I thought I was; I'm the Me Seeker, selfish to the core, sinful to the point of being blind to my own sin and to my own self-deception of thinking I'm a Truth Seeker when I'm really not.)