Verse 18. - If Satan also be divided against himself, how shall his kingdom stand? because ye say that I cast out devils through Beelzebub. Throughout this argument Jesus assumes the existence of a kingdom of evil, all armed and thoroughly organized to carry out its dread purposes. He concedes, too, in language which admits of no questioning, the existence of a chief of this evil confederacy. Throughout his reply, the Master, while carefully bearing in mind the ability and skill of his enemies who had suggested this questioning to the people, addresses himself to the common sense of the mixed multitude who were present on this occasion. The argument is perfectly simple. It is not thinkable that the prince of evil would fight against himself, which he would be doing if he put such mighty weapons into Jesus' hands.

11:14-26 Christ's thus casting out the devils, was really the destroying of their power. The heart of every unconverted sinner is the devil's palace, where he dwells, and where he rules. There is a kind of peace in the heart of an unconverted soul, while the devil, as a strong man armed, keeps it. The sinner is secure, has no doubt concerning the goodness of his state, nor any dread of the judgment to come. But observe the wonderful change made in conversion. The conversion of a soul to God, is Christ's victory over the devil and his power in that soul, restoring the soul to its liberty, and recovering his own interest in it and power over it. All the endowments of mind of body are now employed for Christ. Here is the condition of a hypocrite. The house is swept from common sins, by a forced confession, as Pharaoh's; by a feigned contrition, as Ahab's; or by a partial reformation, as Herod's. The house is swept, but it is not washed; the heart is not made holy. Sweeping takes off only the loose dirt, while the sin that besets the sinner, the beloved sin, is untouched. The house is garnished with common gifts and graces. It is not furnished with any true grace; it is all paint and varnish, not real nor lasting. It was never given up to Christ, nor dwelt in by the Spirit. Let us take heed of resting in that which a man may have, and yet come short of heaven. The wicked spirits enter in without any difficulty; they are welcomed, and they dwell there; there they work, there they rule. From such an awful state let all earnestly pray to be delivered.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.