The idea of entering into the Master’s joy is a telling picture of Heaven. It’s not simply that being with the Master produces joy in us, though certainly it will. Rather, it’s that our Master himself is joyful. He takes joy in himself, in his children, and in his creation. His joy is contagious. Once we’re liberated from the sin that blocks us from God’s joy and our own, we’ll enter into his joy. Joy will be the very air we breathe. The Lord is inexhaustible — therefore his joy is inexhaustible.
Randy Alcorn, Heaven (Carol Stream, IL: Tyndale, 2004), 223.