THE CHURCH
The visible church is all the people who get together from time to time in God's name. Anybody can find out who they are by going to church to look.
The invisible church is all the people God uses for his hands and feet in this world. Nobody can find out who they are except God.
Think of them as two circles. The optimist says they are concentric. The cynic says they don't even touch. The realist says they occasionally overlap.
Frederick Buechner