Dear Brothers and Sisters,
Holy Communion is the third of the sacraments of initiation. In this sacrament the individual makes a regular commitment to Christ and it is sealed by reception of communion.
Communion is called a sacrament of initiation because it is the final seal and ceremony of allegiance between Christ and the individual. It is the completion of the baptismal promise and the final seal of the promises made and received at confirmation.
The candidate or recipient of communion needs to be a Catholic in full communion with the church who is in a state of grace. A non-Catholic Christian is not admitted to Catholic communion because they are (whether they know it or admit it or not) in a state of schism from the fullness of Christ’s Church. To put it simply, they are not full members of the family so they should not receive the sign and seal of that full commitment. Therefore, they should refrain from receiving communion.
If a person is aware of a mortal sin in their life or are aware that they are living in a state of life (like an irregular marriage) then they are not in a state of grace and should not receive. To return to a state of grace we should make an honest Act of Contrition and go to confession as soon as possible. Until they do, they should refrain from receiving communion.
The proper minister of Holy Communion is a validly ordained Catholic priest. Therefore, the communion service of a non-Catholic group is not a valid Catholic Eucharist. It may be a worthy and uplifting act of Christian worship, but it is not a valid Catholic Mass and Catholics are not to receive communion at a non-Catholic communion service. To do so is to give a false witness. An “extraordinary minister of holy communion” is a properly trained and authorized lay person. While this person (and the holy deacons) may administer communion, they are not authorized to celebrate Mass.
The proper form for a valid Mass is the authorized Catholic Missal and the proper matter for the Eucharist is unleavened bread and the pure, fermented wine of the grape.
When we see communion as part of a “little holy trinity” of the three sacraments of initiation we can see why reception of communion is restricted to Catholics. Communion is part of baptism and confirmation. To receive it without being confirmed as a Catholic is to be missing an important part of the whole rite of initiation.
It is important to understand the reason for these disciplines of the church so that we can not only uphold them, but also explain them to others when we need to.