Jesus had a pet topic. Bible writers usually call it by one of two names: kingdom of heaven or kingdom of God.
It’s not a substitute word for “heaven.” It’s the kingdom that God rules in heaven and on earth. Jesus spent much of his time teaching people about this kingdom-what It’s like and how to live as kingdom citizens.
Jesus often used word pictures to describe it.
When asked who the greatest person in this kingdom is, Jesus called over a child. Then he said, “Anyone who becomes as humble as this little child is the greatest in the Kingdom of Heaven” (Matthew 18:4).
He used parables, too. A shepherd leaves his flock of 99 sheep to find one missing sheep. When he finds it, he rejoices. Jesus said God rejoices, too, when a lost person returns to the heavenly kingdom where he belongs.
Finding lost sheep is the ministry of Jesus. And it’s the ministry he passes on to his disciples.