What Does the Bible Say About the Kingdom of God‪?‬

Sometimes Jesus talked about the kingdom of God as if it were already here, and sometimes he talked as if it were far in the future. Which is it, and how does it affect life right now? Another way to approach the question is to observe that Jesus preached about the kingdom of God, but his disciples preached about Jesus. Why this difference in focus, and why does it matter for us today?