2 But now that they may not think that it is the prince of the devils in whom the Lord Jesus Christ casts out devils, let them attend to what follows; “And if I,” He says, “by Beelzebub cast out devils, by whom do your children cast them out? Therefore shall they be your judges.” He spoke this undoubtedly of his disciples, the “children” of that people; who as being the disciples of the Lord Jesus Christ were well conscious that they had learned no evil arts from their Good Master, that through the prince of the devils they should cast out devils.
“Therefore,” He says, “shall they be your judges.” They, He says, the base and contemptible things of this world, in whom none of this artificial malice, but the holy simplicity of My power is seen; they shall be My witnesses, they shall be your judges. Then He subjoins, “But if I by the Spirit of God cast out devils, then the kingdom of God has come unto you.” What is this? “If I by the Spirit of God cast out devils,” He says, and your children, to whom I have given no hurtful and deceitful doctrine but a simple faith, can in no other way cast them out; no doubt the kingdom of God has come unto you; whereby the kingdom of the devil is subverted, and you also are subverted with it.
Source: Sermons on Selected Lessons of the New Testament (New Advent)