Fr. Joseph Iannuzzi: "An interior reign of Christ not an exterior. Between the reign of Christ and the coming of Christ in the flesh their will be a period of peace on earth and a springtime of Christianity as Pope John Paul II put it, 

where Christ will reign in all the earth’s inhabitants thereby making them ‘living Hosts’ where sin will be
modified, not completely done away with. 

Satan will be enchained during this period as the Book
of Revelation reports but all humans on earth will still during this period of peace on earth be conceived with Original Sin and therefore need the Seven Sacraments as well but the difference they will live in peace and harmony but sin will be modified. 

There will be a holy nation, a royal priesthood, a kingdom of priests as St Peter says where the meek will inherit the earth and as Saints Pope John XXIII and John Paul II said there will be a ‘New Pentecost’.

The encyclical of Pope John II entitled ‘On the Threshold of the Third Millennium’ which affirms that
Christianity is on the threshold of a New Millennium, which will bring a springtime of the rediscover
of the Church’s holiness &amp; a new era in the life of the Church. 

Before His coronation, Cardinal Ratzinger acknowledged that his predecessors’ words concerning the new millennium alluded to Paul’s letter to the Romans where it says ‘creation groans with eager longing for the revelation of the sons of God’.

Creation will be set free from its slavery to corruption and obtain the glorious freedom of the Sons of God. 

Cardinal Ratzinger whilst prefect for the Congregation for the Doctrine of the Faith states in quotes ‘and we hear today the groaning of creation as no one has
ever heard it before the Pope’s expectation that the Millennium of divisions will follow the Millennium of Unifications.’

This quote of Cardinal Ratzinger of a Millennium of unity is taken from a work titled ‘Salt of the Earth’ published 1997 p 237.