In Matthew 12:24-31, Jesus says:
24 But when the Pharisees heard this, they said, “This man casts out demons only by Beelzebul the ruler of the demons.” 25 And knowing their thoughts Jesus said to them, “Any kingdom divided against itself is laid waste; and any city or house divided against itself will not stand. 26 If Satan casts out Satan, he is divided against himself; how then will his kingdom stand? 27 If I by Beelzebul cast out demons, by whom do your sons cast them out? For this reason they will be your judges. 28 But if I cast out demons by the Spirit of God, then the kingdom of God has come upon you. 29 Or how can anyone enter the strong man’s house and carry off his property, unless he first binds the strong man? And then he will plunder his house...31 Therefore I say to you, any sin and blasphemy shall be forgiven people, but blasphemy against the Spirit shall not be forgiven." Matthew 12:24-31 (NASB)
The context of Jesus' remarks regarding blasphemy against the Holy Spirit seem to indicate it is related to attributing the work of the Holy Spirit to Satan.
It appears to me that Jesus' words do not deal with the possibility of deception on Satan's part (a being whose very existence is devoted to misleading human beings) . That is, Satan could "fake" an exorcism by releasing someone from demonic influence, only to influence that person in more subtle and dangerous ways, as well as misled witnesses.
The possibility of Satan being the source of powerful works is commonly appealed to in order to explain or denigrate miracles, even exorcisms, that occur in groups whose theology contradicts one's own, and especially those acts of power (that might bring relief to someone, such as healing) which occur outside the context of Christianity.
This seems to be the very sin the Pharisees were committing, since an act of power that visibly brought relief to a human being challenged their commitments and beliefs, and thus came their attempt to protect their worldview by calling that which was visibly good, wicked. It is also altogether plausible that they would have appealed to Satan being a deceiver to further their argument against Jesus.
On the basis of Jesus words, are we to conclude that a Christian must admit that a powerful work that has evidence of bringing healing, relief, or freedom from some sort of wicked spiritual influence, especially one performed in the context of Christianity, is from God, otherwise he or she might be blaspheming against the Holy Spirit?
Does Jesus' argument that Satan cannot cast out Satan indicate he is unable to exorcise a demon as a kind of ruse with some wicked intent such as deception?