This week marks the annual Week of Prayer for Christian Unity. This ecumenical effort is not merely a nice thing to do, but it is indeed a command of the Lord Jesus, from His priestly prayer in the 17th chapter of the Gospel of John – “Ut Unum Sint,” or “That they might be one.” It is the Lord’s will that all of His followers be one in Him, as He is in the Father and the Holy Spirit.

Christian unity has proven to be a challenge, to say the least. Not only because of our fallen human nature, but also because of truly significant doctrinal difference, we are not yet one. Yes, we share a common baptism and a common faith that Jesus is Lord, but we cannot simply have a least common denominator Christianity, filled with vagaries and nice aphorisms.

We need to acknowledge the differences that exist with our Sister Church, the Orthodox, and with the different ecclesial communions, like the Lutherans, the Episcopalians, etc. We hold some very different opinions on matters of ecclesiology, of sacramental reality and of morality. To fail to acknowledge these differences and to state “we’re ultimately all the same, right?” is to not tell the truth.

We believe some very different things, for instance, about the Substantial Presence of Christ in the Eucharist compared to a Lutheran or an Episcopalian. We need to look no further than the Anglican Communion’s actions towards the Episcopal Church U.S.A. this week over issues of same-sex marriage, resulting in a suspension of that particular branch of the Anglican Communion.

“Given the seriousness of these matters we formally acknowledge this distance by requiring that for a period of three years The Episcopal Church no longer represent us on ecumenical and interfaith bodies . . . ” the Anglican Communion wrote in its statement. “They will not take part in decision- making on any issues pertaining to doctrine or polity.” This is indeed quite serious, and the Episcopal Church U.S.A. has taken a very different stance on same-sex marriage than we in the Catholic Church.

Yes, there are indeed divisions, and some can and do result in a severe cleavage between the Catholic Church and our brothers and sisters in Christ who are Protestant and Orthodox Christians. Yet, still we strive for the Lord’s command to be done – “Ut Unum Sint!”

On the international level, the Vatican is in dialogue; on the national level, the United States Conference of Catholic Bishops is in dialogue; on the diocesan level, the Diocese of Brooklyn is in dialogue; and yes, even on the parish level, on a lived, practical manner, the Catholic Church and other local Christian denominations are in dialogue, engaging in all levels of social outreach.

One area of ecumenical division that seems to be taking a turn in dialogue is the role of Mary. Long a figure of discussion and division between Catholics and Protestants, she is now being recognized as a key and central figure in Christianity by the different churches.

During this Week of Prayer for Christian Unity, when we strive for the unity of all Christians, perhaps we Catholics can turn to Mary, the Mother of the Church, and beseech her to beg her Son to bring unity in all our relationships, especially with our neighbors who are not in communion with us.

“Ut Unum Sint,” not just a suggestion, but a Divine Command from the One who is Mercy himself.