What does Mark 3:25 mean?

The scribes who came down from Jerusalem said, “He has Beelzebul,” and, “By the prince of the demons he casts out the demons.”

He summoned them, and said to them in parables, “How can Satan cast out Satan?

If a kingdom is divided against itself, that kingdom cannot stand.

If Satan has risen up against himself, and is divided, he can’t stand, but has an end.

But no one can enter into the house of the strong man to plunder, unless he first binds the strong man; and then he will plunder his house.

Most certainly I tell you, all sins of the descendants of man will be forgiven, including their blasphemies with which they may blaspheme;