Luke 11:17

But he, knowing their thoughts, said unto them, Every kingdom divided against itself is brought to desolation; and a house divided against a house falleth.

The amazing similarity of the synoptic Gospels in their records of the teaching here, coupled with the equally amazing differences, presents a problem that may be resolved fully and satisfactorily only by understanding them as independent, trustworthy records of different events; and this writer agrees with A. T. Robertson, who, in his "Harmony of the Gospels," made Mark and Matthew parallel and Luke independent in this section.[24] See the introduction to this chapter. Hobbs also observed that although some of these events and teachings are recorded in Mark and Matthew as having taken place in Galilee, "There is no reason why they could not have taken place in Judea also. His enemies followed him here, as in Galilee; the hearers were different and had not heard the teaching before."[25]

Every kingdom divided ... etc. The argument here is that Jesus' action was not BY the devil, but AGAINST him, and that if Satan was working through Jesus he was working against himself.

[24] A. T. Robertson, A Harmony of the Gospels (New York: Harper and Brothers, 1922), p. 124.

[25] Herschel H. Hobbs, An Exposition of the Gospel of Luke (Grand Rapids, Michigan: Baker Book House, 1966), p. 192.