What does Mark 1:34 mean?
In Jesus' last encounter with the masses (Luke 5:1–3), He taught, but no mention of healing is given. Now, hours after healing a demon-possessed man and an ill woman (Mark 1:21–31), He is swarmed with an entire town wanting to be healed. Jesus responds. Illness and demon possession are not necessarily direct results of sin (John 9:1–3), but they are ultimately related. Illness is a result of Adam and Eve's original sin that makes our bodies frail and our world deadly. Possession is because of Satan's rebellion against God. Jesus certainly came to rescue us from the results of sin, but not necessarily in this way. In His grace, He healed the sick, but this was not His priority. The next morning, He will tell His disciples "Let us go on to the next towns, that I may preach there also, for that is why I came out" (Mark 1:38). Jesus came to heal us permanently by restoring our relationship with God. This is the gospel He came to preach; the rest was frosting.Jesus not only expelled the demons from their victims, He prevented those demons from speaking. Here we find three interesting observations. First, demons can speak, or at least control their victims' speech. Second, these demons knew who Jesus was. Third, Jesus did not permit the demons to speak when around Him. They sought to disrupt His plans, something Jesus would not allow. His plan—to reveal Himself as the Messiah, God, and the Son of God—was not served by the testimony of His enemy. One of Satan's favorite tools is to twist the truth to his own ends. Jesus would not let the demons lay a hand on the truth to twist it.
Mark 1:21–45 opens a longer section describing the healing and preaching ministry of Jesus Christ. In this segment, Jesus impresses onlookers with His mastery of the Scriptures. He also amazes people with His authoritative style. During this teaching, Jesus heals a man afflicted with demonic possession. The resulting publicity brings a massive crowd to the home of Simon Peter, where Jesus is staying. Jesus heals Peter's mother-in-law of a fever, and cures a leper, before leaving the region to continue His ministry.
John the Baptist is introduced as a figure preparing the world for the arrival of the Messiah. John's baptism teaches people about their need for repentance. When Jesus arrives, and is baptized, it signals the coming of God's fulfillment and the need of people to recognize their Savior. Mark briefly notes Jesus' baptism, desert temptation, and the calling of the first four disciples. After this, Jesus begins teaching in the synagogue and performs miraculous healings which spread His fame around the region.