Communion in non-Orthodox Churchesl
Fr. John Matusiak, Orthodox Church in America (OCA)
Orthodox Christianity does not permit its faithful to receive Holy Communion in non-Orthodox communities, whether they be Roman Catholic, Protestant, or whatever. Hence, while Roman Catholicism may extend Eucharistic hospitality to Orthodox Christians, it does not mean that Orthodox Christians are permitted to accept such hospitality.
For Orthodox Christians, the Eucharist is a visible sign of unity; to receive the Eucharist in a community to which one does not belong is improper. If one does not accept all that the Church believes and teaches and worships, one cannot make a visible sign of unity with it. The Eucharist is the result of unity, not the means by which unity is achieved. While many non-Orthodox see this as a sign that the Orthodox Church excludes non-Orthodox from the Eucharist, in reality the opposite is true. Because a non-Orthodox individual has chosen not to embrace all that Orthodox Christianity holds, the non-Orthodox individual makes it impossible for an Orthodox priest to offer him or her communion. It is not so much a matter of Orthodoxy excluding non-Orthodox as it is the non-Orthodox making it impossible for the Orthodox to offer the Eucharist.
Sometimes people argue, "But Father, I believe everything the Orthodox Church teaches." If this is indeed the case, then the question is not one of Eucharistic hospitality but, rather, "Then if you believe everything the Orthodox Church teaches, why haven't you become an Orthodox Christian?"