Luke 11:18

And if Satan also be divided against himself, how shall his kingdom stand ?.... This is the accommodation of the above parables, or proverbial sentences; suggesting, that Satan must be against himself, if what the Pharisees said was true; and consequently, his kingdom and government, could not long subsist:

because ye say that I cast out devils through Beelzebub ; which is all one as to say, that Satan is divided against himself, which is not reasonable to suppose; See Gill on Matthew 12:26 and See Gill on Mark 3:26 .