In the Gospels of Mark and Luke Jesus talks about the "Kingdom of God." In Matthew's Gospel he talks about the "Kingdom of Heaven." Because Matthew is a Jew, he substitutes "Heaven" for "God," but the phrase in all three Gospels points to the same Mystery.
Before we began using the three year cycle lectionary in the 70's, every year the Gospel used was almost always Matthew's, so we most often heard "Kingdom of Heaven." This led most of us to think that Jesus was talking about the place we go after dying.
The Greek word "basileia" refers, not to a place, but to the act of ruling. Instead of "Kingdom" many modern translations have "Reign of God," "Rule of God," "Dominion of God." Jesus is talking about God's act of ruling us and our whole world.
Since I often substitute "Love" as a name for God (1 John 4:8,) I come up with "The Reign of Love."
In Luke 4:43 Jesus says, "I must proclaim the Good News of The Reign of Love."