Albert Barnes Commentary Matthew 12:30

"He that is not with me is against me, and he that gathereth not with me scattereth." — Matthew 12:30 (ASV)

He that is not with me, etc. In addition to his other arguments, he urges this general principle: that there could only be two parties in the universe. If anyone did not act with him, he was against him. If he did not gather with him, he scattered.

This principle is taken from the practice of people in harvest: one who did not gather with him, or aid him, scattered abroad, or opposed him. The application of this was, "Since I have not united with Satan, but opposed him, there can be no league between us." Therefore, the charge is false.