With the apostolic letter “In unitate fidei”, Leo XIV calls Christians to be a sign of peace

The papal plane will take off this Thursday, November 27 for three days in Türkiye, before reaching Lebanon. A first trip outside Italy with multiple challenges, and above all an important anniversary for the Church: in 325 the first ecumenical council in the history of Christianity was held in Nicaea (current Iznik). In an apostolic letter published on November 23, Leo XIV remembered the event and highlighted its relevance.

A troubled history

The pope first returns at length to the very history of the Council, which opened while “the wounds of the persecutions against Christians were still raw”. If Christianity had been admitted in the Roman Empire for around twenty years, “disputes and conflicts quickly emerged within the Church.”

It was also to respond to the Egyptian monk Arius, who taught that Christ was not the Son of God, that the Council met. As the pope recalls, it is at the initiative of the Emperor Constantine himself, who sees social peace and political unity threatened by these theological quarrels, that this assembly is being held.

Of the 318 “Fathers” who came to participate, a majority came from the Orient. Leo XIV focuses particularly on the figure of Saint Athanasius, deacon in Alexandria and main opponent of Arius. The latter insists on the importance of the divinity of Christ: if God becomes man, it is to divinize men.

A Creed for Today’s Faith

The whole challenge for the Council is to state the content of the Christian faith. First in one God, Father, Son and Holy Spirit. Then in a God who “made himself close to us and came to meet us in Jesus Christ.” Finally, in a God “who wants us to have life, and to have it in abundance,” and who to do this gave his life for men.

Leo XIV then invites Christians to question the relevance of this age-old message in their personal life of faith: “Do we have the feeling that it also concerns our current situation? (…) What does what we say mean for our lives?” And the pope warns: “The Nicene Creed therefore invites us to examine our conscience. What does God mean to me and how do I demonstrate my faith in Him?

Unity of the Church

The text ends with a call for the unity of the Church, of which the Nicene Creed is the cornerstone. “We share faith in one and only God, Father of all men, we confess together the one Lord and true Son of God Jesus Christ and the One Holy Spirit (…). What unites us is truly greater than what divides us!” For the Pope, there is an urgent need for Christians to come together around this common deposit of faith, to become “a sign of peace and an instrument of reconciliation” in the middle of a world torn by wars.

While avoiding the double pitfall of going backwards and getting stuck in the status quo, Leo

The issues raised by the text are not less. In Türkiye, Leo XIV will meet Patriarch Bartholomew I, primate of the Orthodox Church of Constantinople. In this country, as in Lebanon, Christians are largely in the minority. For them, the pope’s arrival is a strong sign.