What does it mean to pray "your kingdom come"?  Brad Young, in his book on the Lord's Prayer, states: 
Probably no other aspect of Jesus teaching has been so greatly misunderstood as the kingdom of heaven. Certainly, no other theme is more essential for understanding Jesus.
It's a concept  at the very heart of the Jewish faith, and of Jesus' mission, not to mention the subject of the vast majority of his parables.  Let's spend a few minutes defining it.
Scripture: Matthew 6:10