Response from: Fr. Bo and Fr. Stephen
Perhaps I should explain.
We recognize that, as Ukrainian Catholics, we have the same faith, liturgy, spirituality, traditions as the Orthodox, and that praying together is and would be a positive thing. In fact, we welcome opportunities to pray together. Locally we join together in November at City Hall with our Ukrainian Orthodox brothers and sisters to pray in commemorating the artificial famine imposed on Ukraine by the Soviet government in 1932-1933 – the Holodomor. As well, we pray together every August at the Ukrainian Village for our early Ukrainian pioneers in Canada. We have also prayed in each other’s churches for special occasions as when Ukrainian Catholics were invited to join the Ukrainian Orthodox at their cathedral to celebrate the 100th anniversary of the establishment of the Ukrainian Orthodox Church in Canada.
Still we are a church divided. This division is seen predominantly in how Catholics and Orthodox approach the sharing of sacraments.
The Code of Canons of the Eastern Churches permits, under certain circumstances, the sharing of the sacraments of Eucharist, Penance and Anointing of the Sick. Therefore Ukrainian Catholic priests may administer these sacraments to the Orthodox who “ask for them on their own and are properly disposed” (Canon 670, #3). Generally, most Orthodox churches do not permit Catholics to receive the Eucharist, even though Eastern Catholic Canon Law would allow it if “necessity requires it or genuine spiritual advantage suggests it” (Canon 671, #2). In addition, the Code cautions against the belief that differences of religious belief are of no importance, however, the Code does recognize Orthodox sacraments as valid.
The reason why there is a discrepancy here is that the two churches are not in full communion (yet). Orthodox Churches recognize that if we are not in full communion with each other, then we cannot share in the Eucharist which is a sign of unity. In essence, they believe that sharing Eucharist and saying we are one would be untruthful. There are many Catholics and Orthodox, however, who believe that we need to share Eucharist to become fully in communion with one another because Eucharist is the medicine that brings people and God into communion with each other. Equally, many members of both churches long for communion (sadly some seem to be happy with the division and propagate it) so that we can be one as Jesus and the Father are one (see Jesus’ prayer for unity in John 17).
Let’s do what we can to love each other and grow closer to each other. Then there will be no “Catholic” and no “Orthodox”, but only One truly Catholic Orthodox church.
So, there is no sin for a Ukrainian Catholic in attending an Orthodox service, especially when one cannot attend a Ukrainian Catholic service. However, we do need to receive the Eucharist to be nourished. Therefore, attending Catholic Churches is necessary for Catholics.