Introduction
On November 23, 2025, the Solemnity of Christ the King, coinciding with the 1700th anniversary of the Council, Pope Leo XIV issued the Apostolic Letter In Unitate Fidei (In the Unity of Faith) for the faithful. While embracing theological diversity, the Pope calls through this document for unity and reconciliation, encouraging the Churches to walk together toward deeper communion, cooperation, and witness.
Issued a few days prior to his Apostolic Visit to Turkey, the document offers profound reflections on the theological, social, and cultural relevance of the Council of Nicaea. Presented in twelve sections, the principal themes of the Apostolic Letter are outlined below.
1. Who is Jesus?
“Who do you say that I am?”-the question Jesus asked Peter at Caesarea Philippi remains relevant even today, the Pope reminds us. Arianism is not merely a historical error; its temptations persist even now. It manifests as the tendency to view Jesus as a mere intermediary, a being who is not fully divine. The denial of Christ’s divine nature in communion with the Father continues in various forms-seeing Jesus merely as a moral teacher, a spiritual leader, or a divine force. Therefore, the Pope reiterates without ambiguity the Council’s teaching on who Jesus is: the Firstborn of the Father, uncreated, and consubstantial with the Father.
2. The Divinity of the Son is Essential for Human Salvation
Only God can accomplish human salvation. If Jesus were not fully divine, salvation would not be possible. Citing the Fathers of the Church, the Pope explains the inner meaning of the Incarnation. The Incarnation is the fullest expression of God’s love for humanity, and through it, the human person-body and soul-is redeemed. If this truth is not professed, Christianity would be reduced to a mere moral-philosophical system.
3. Modern Forms of Arianism
For Arius, the Son was an intermediary being, incapable of fully knowing the Father and subject to change. According to the Pope, similar ideas persist today: Christianity is merely an inspiration, Jesus is an exceptional prophet, and God is only a spiritual energy. Through this Apostolic Letter, the Pope analyzes the salvific value granted to humanity through God becoming man and reaffirms the reality of the Incarnation.
4. Unity of Faith: Communion in Truth
Complete unity in the truth that is Christ forms the foundation of relationships among the Churches. The Council of Nicaea guided the Church toward this truth. The Nicene Creed is not merely a historical event; it continually calls us to profess this faith anew. Only by remaining rooted in this faith can the Churches endure and move forward. The Pope stresses that the Church must never lose Christ. Only where Jesus is fully God and fully man does Christianity remain the true Gospel.
Conclusion
We must walk together toward unity and reconciliation among all Christians. Unity without diversity becomes authoritarianism, while diversity without unity leads to fragmentation, the Pope emphasizes. Christian unity does not impoverish us; rather, it enriches us. As at Nicaea, this unity will be achieved through a long and demanding journey of mutual listening, acceptance, patience, repentance, and conversion-a profound spiritual challenge for all.
Rev. Dr. Varghese Kochuparambil
