MKJV Luke 4:31-40 And He came down to Capernaum, a city of Galilee, and taught them on the sabbath days. (32) And they were astonished at His doctrine, for His word was with authority.
What kind of authority did Jesus have?
MKJV (33) And in the synagogue there was a man who had a spirit of an unclean demon and cried out with a loud voice, (34) saying, Let us alone! What is to us and to You, Jesus of Nazareth? Have You come to destroy us? I know You, who You are, the Holy One of God. (35) And Jesus rebuked him, saying, Be quiet and come out of him! And when the demon had thrown him into the midst, he came out of him, not harming him. (36) And they were all amazed and spoke among themselves, saying, What a word is this! For with authority and power He commands the unclean spirits, and they come out.
Jesus clearly had authority over the demon, and because of that he did not pray for the man but simply commanded the unclean spirit, and it came out. Verse 35 tells us that Jesus rebuked the demon by issuing a command to it to “be quiet and come out of him!” When you have authority over something—like your pet dog—you don’t pray and ask God to command it. Rather you yourself issue the command, and it should obey you. Whatever is under your authority must and will obey your command.
NIV (37) And the news about him spread throughout the surrounding area. (38) Jesus left the synagogue and went to the home of Simon. Now Simon’s mother-in-law was suffering from a high fever, and they asked Jesus to help her. (39) So he bent over her and rebuked the fever…
Here Simon’s mother-in-law is simply physically sick with a bad fever; she’s not demonized like the man in the synagogue. But notice that Jesus takes the same action as he did for the demonized man: he rebukes the fever just as he rebuked the demon in the man. The Greek verb for “rebuke” is the same in both cases: ἐπιτιμάω or epitimaō. Just as Jesus issued a command to the demon in the man to leave, in the same way he issued a command to the fever afflicting Simon’s mother-in-law—most likely something to effect of “leave” or “go!”
…and it left her. She got up at once and began to wait on them.
The fever obeyed the Lord’s command to leave and the woman was healed.
Later in Luke 9 we see Jesus giving this power and authority to his disciples for proclaiming the kingdom of God to the lost and for healing the sick—exactly as He did.
(NIV) Luke 9:1-2 When Jesus had called the Twelve together, he gave them power and authority to drive out all demons and to cure diseases, (2) and he sent them out to proclaim the kingdom of God and to heal the sick.
Disciples can exercise this authority both to heal the sick as well as to cast out demons as Jesus did. This is done by issuing commands to infirmities in the case of sickness, and in the same way issuing commands to unclean spirits in the case of demonization. Because the Lord has placed them under our authority, infirmities and demons must obey our commands and leave in Jesus’ name.