The Bible, in the New Testament, shows Jesus casting out demons. If Jesus cast out demons then there is nothing wrong with Christians in the New Testament Church casting out demons. We are supposed to imitate the ministry of Jesus Christ as He was and is our example. There is nothing wrong with having your favorite Bible teacher, Pastor or Bishop, however, Jesus is the One that we are supposed to ultimately follow.
Not only was Jesus able to cast out demons but so were his disciples.
The following scripture show that power of Jesus and His ability to cast out demons and that the demons were ALWAYS subject to Him. But the Bible shows that they were also subject to the disciples.
Matthew 8:16 …they brought to Him [Jesus] many who were demon-possessed. And He cast out the spirits with a word, and healed all who were sick
Mark 1:23-27 Now there was a man in their synagogue with an unclean spirit. And he cried out, saying, “Let us alone! What have we to do with You, Jesus of Nazareth? Did You come to destroy us? I know who You are — the Holy One of God!” But Jesus rebuked him, saying, “Be quiet, and come out of him!” And when the unclean spirit had convulsed him and cried out with a loud voice, he came out of him. Then they were all amazed, so that they questioned among themselves, saying, “What is this? What new doctrine is this? For with authority He [Jesus] commands even the unclean spirits, and they obey Him.”