Testimony of the unclean spirit
Mark 1:21 And they went into Capernaum; and straightway on the sabbath day he entered into the synagogue, and taught.
Jesus and those he had chosen as disciples were with him as he journeyed to Capernaum, Jesus had just begun his ministry. The law required that to be a priest one had to be thirty years of age. The disciples were to learn from Jesus. They followed him because of the testimony of the prophet, John the Baptist.
Mark 1:22 And they were astonished at his doctrine: for he taught them as one that had authority, and not as the scribes.
What was Jesus like when he preached? Like no other, they were astonished at his teachings. He spoke the word of God with authority, being himself the Son of God, come in the flesh. No one really knew this was God speaking; but the spirit world knew who Jesus was.
Mark 1:23 And there was in their synagogue a man with an unclean spirit; and he cried out,
Mark 1:24 Saying, Let us alone; what have we to do with thee, thou Jesus of Nazareth? art thou come to destroy us? I know thee who thou art, the Holy One of God.
A man in the synagogue, it could be a man in a church, but when Jesus was in his presence he cried out! What spirit is this? It is a fallen spirit, probably angels that had fallen with Lucifer, the angel of light, the devil. These know the spiritual powers. They saw the Holy one of God, God the Word, the Son of God, in the man Jesus. They also knew that this Word of God would judge them and cast them into the lake of fire. They were afraid that their time was up. They would be judged by his word and cast into the lake of fire after his second coming. Still he had power and authority even over the angels and demons.
Mark 1:25 And Jesus rebuked him, saying, Hold thy peace, and come out of him.
Mark 1:26 And when the unclean spirit had torn him, and cried with a loud voice, he came out of him.
The unclean spirit had to come out at the command of Jesus. He tore him. Often to cast out a devil, in my experience, there is discomfort, headache, or nausea, it is the unclean spirit trying to cause the person to turn from the spiritual to the needs of the body.
So the disciples themselves witnessed the power of the word and the authority of Jesus. The unclean spirit was the first to see Jesus as he was, the first was the witness of the prophet John. Also the witness of the Father and the Holy Spirit at his baptism.
Mat 3:17 And lo a voice from heaven, saying, This is my beloved Son, in whom I am well pleased.
Mark 1:27 And they were all amazed, insomuch that they questioned among themselves, saying, What thing is this? what new doctrine is this? for with authority commandeth he even the unclean spirits, and they do obey him.
Mark 1:28 And immediately his fame spread abroad throughout all the region round about Galilee.
The people were amazed as well and he became famous. This would make their religious leaders envious. With every victory, the enemy sends in more of his dark ones to interfere with the moving of God. Expect it, success will be followed by attacks, but in the name of Jesus is power and authority over all things.