What does Mark 1:14 mean?

Following a cursory mention of Jesus' baptism (Mark 1:10–11) and temptation (Mark 1:12–13), the second of seven sections in Mark introduces Jesus' ministry and the call of the disciples (Mark 1:14–20). God interacts with people in different ways depending on the era. In the time of Israel in the Old Testament, He communicated through prophets, and John the Baptist was the finale. John was arrested for challenging Herod the tetrarch's marriage to his own sister-in-law. Though Herod was afraid of John because he was so popular, Herod's wife demanded John be arrested, and arranged for his execution (Matthew 14:1–12). As John the Baptist's arrest takes him out of the picture, Jesus starts His public ministry (Matthew 4:12–17). This is not out of any callousness, but because it is time for God to communicate with His people directly through His Son.

Galilee is a region on northern Israel, west of the Sea of Galilee, in the area once claimed by the tribes Zebulun and Naphtali of the Northern Kingdom of Israel (Isaiah 9:1). Nazareth, where Jesus grew up (Matthew 2:22; 3:13), sits very near the center, while Capernaum is about forty miles northeast on the northwest coast of the Sea. Jesus starts His ministry of teaching the gospel of God near His home, not in the social/religious center of Jerusalem. "Gospel," from the Greek euaggelion, means "glad tidings," specifically about the salvation that Jesus offers. While John's message reminded the people that they needed forgiveness, Jesus' message shows them how to receive that forgiveness.