<P> "A Holy Door...is a visual symbol of internal renewal, which begins with the willing desire to make peace with God, reconcile with your neighbors, restore in yourself everything that has been damaged in the past, and reshape your heart through conversion ." </P> <P> In 1975, Pope Paul VI, in light of the modernising changes of the Second Vatican Council revised the rite by removing the use of trowel and ornate bricks at the closing rite . </P> <P> Pope John Paul II further simplified the ceremony for the Great Jubilee of 2000 for safety reasons; previously, debris had fallen on Pope Paul VI while striking down the door . Workers had removed the concrete before the ceremony of the opening of the door so that the Pope only had to push on the doors with his hands . The holy door of St. Peter's Basilica was opened by the Pope on 24 December 1999 while the doors of St. John Lateran and St. Mary Major were opened on 25 December and 1 January, respectively . Breaking with tradition, the Pope opened both of these personally, rather than delegating this to a cardinal . The doors of Basilica of Saint Paul Outside the Walls were opened in an ecumenical ceremony on 18 January, first day of the World Week of Prayer for Christian Unity by the Pope, the Archbishop of Canterbury and a representative of the Ecumenical Patriarch . The door in St. Peter's was closed on 6 January 2001, with the others being closed one day earlier . </P> <P> Until the Great Jubilee of 2000, the Pope knocked upon the door three times with a silver hammer, singing the versicle "Open unto me the gates of justice". Above the holy door in St. Peter's are marble memorial plates commemorating the last two times that the door has been opened . Since John Paul II held the last two Jubilees, both plates indicate that he opened and closed the door . </P>

What does closing the door of mercy mean