The preaching of Jesus is summarized in his announcement that the kingdom of God had come. He called people to repent (turn away from sin and turn to God) and believe the good news about the Messiah (1:1).
The kingdom of God is not associated with a place or land. It began with Jesus himself and continues through his followers.
Because the kingdom of God has come, people must repent and have faith in God's good news. In the time of Jesus, this good news meant that God’s reign had arrived through the Messiah. For Mark’s later audience, it also included the news of the death, resurrection, ascension of Jesus, and his promised return (15:1–16:8).
All people, both Jews and non-Jews (called Gentiles), need God's forgiveness through repentance and faith in Jesus.