Please read the passage before the commentary.
If you ascribe the signs and wonders Jesus has done to demons, then you are admitting that the devil is fighting against itself, which makes no sense at all. If you ascribe God’s workings to the devil, then you are accusing God of doing the devil’s work, which amounts to blasphemy. Again, if the devil is so strong, and yet you can beat the devil, then you must be more powerful than the devil. Therefore, Jesus must be conquering the devil and must be working with the power of God.
What work are we doing? If good, then we are using the power God has given us. If bad, we are making alliances with demons. If people were to accuse us of being Christians, could they convict us?
Mark put this episode in a section where he described the family of Jesus. While the blood family of Jesus looked for Jesus, Jesus was sending time with those who were listening to him. Those who follow Jesus are Jesus’ family. Are we part of his family?