68 It is the will of God, the Church's founder, that all the sheep should eventually gather into this one fold, under the guidance of one shepherd. All God's children are summoned to their father's only home, and its cornerstone is Peter. All men should work together like brothers to become part of this single kingdom of God; for the citizens of that kingdom are united in peace and harmony on earth that they might enjoy eternal happiness some day in heaven.
Source: Ad Petri Cathedram (Vatican.va)