That all may be one
"The Eucharist is both the source of ecclesial unity and its greatest manifestation. The Eucharist is an epiphany of communion. For this reason the Church sets conditions for full participation in the celebration of the Eucharist. These various limitations ought to make us ever more conscious of the demands made by the communion which Jesus asks of us. It is a hierarchical communion, based on the awareness of a variety of roles and ministries, as is seen by the reference to the Pope and the Diocesan Bishop in the Eucharistic Prayer. It is a fraternal communion, cultivated by a 'spirituality of communion' which fosters reciprocal openness, affection, understanding and forgiveness."
John Paul II, Apostolic Letter Mane Nobiscum Domine, 21