John envisions a new heaven and a new earth. Things are now different from the way they were; moreover, they are different because God has said so. Furthermore, in this new way of things, God will continue to be in our midst. God will continue to care for us.
Every day, several times a day, we face temptations to bow to the demands of the society around us. We, of course, care about assuring and protecting our own security. But, if we are Christians, since we are Christians, we have to take up residency in this new earth, one with tribes from every nation, everybody speaking different languages. We are all there together, all worshipping God.
Where once heaven and earth seemed so far apart, so separate, now, in Christ, we see heaven coming down to us. Where once we thought of God as far away, so separate, now, we experience God's presence right here, right now.