Mateo 12:30

He that is not with me is against me; and he that gathereth not with me scattereth.

Of this, Boles wrote:

In the great conflict between life and darkness, good and evil, the kingdom of God and of Satan, there is no middle ground; there is no neutral position; there is no third power to which these miracles may be attributed. These Pharisees were obliged either to join Christ or to be against him. They had to become allies of God or co-workers with Satan; there was no other alternative.[6]

Also, since their disciples were doing the same thing, or professing to do so, their judgment of Christ was automatically a judgment of themselves.