The statement from Pope Benedict XVI emphasises that the Kingdom of God is embodied in the person of Jesus Christ rather than in any physical location or abstract concept. Building the Kingdom therefore requires followers to imitate Christ’s life and teachings through concrete actions in the world. This essay examines how Pope John XXIII (Angelo Giuseppe Roncalli, r. 1958–1963) encouraged adherents to pursue this goal. It focuses on three key areas: his decision to convoke the Second Vatican Council, the content and purpose of his major encyclicals, and the subsequent documents produced by the Council itself. Through these initiatives, John XXIII sought to renew the Catholic Church so that it might more faithfully reflect Christ’s message of justice, peace and service.
The Convocation of the Second Vatican Council
John XXIII announced his intention to call an ecumenical council on 25 January 1959, only three months after his election. The announcement surprised many observers, given that the previous council (Vatican I) had ended almost ninety years earlier. He described the council as necessary to promote the unity of all Christians and to address contemporary pastoral needs. By opening the Church to the modern world, John XXIII intended to enable Catholics to participate more effectively in Christ’s work of reconciliation and justice. This decision was rooted in his conviction that the institutional Church must adapt its structures and language in order to communicate the Gospel more clearly, thereby helping believers live out the Kingdom in everyday life.
Encyclicals as Instruments of Social Teaching
John XXIII issued two major encyclicals that explicitly linked the Kingdom with active Christian witness in society. Mater et Magistra (1961) addressed questions of social justice, agriculture, and economic development, urging Catholics to promote the common good in line with Christ’s concern for the poor. Pacem in Terris (1963), addressed to “all men of good will,” presented a detailed vision of peace based on respect for human rights and international cooperation. These documents encouraged adherents to translate the person of Jesus—embodied in the Kingdom—into concrete policies and relationships. While the encyclicals drew upon earlier social teaching, they adopted a more optimistic tone and addressed a global audience. This broader scope reflected John XXIII’s belief that the Church’s role was not merely to preserve doctrine but to foster conditions in which Christ’s peace could be realised.
The Impact of Vatican II Documents
Although the Council continued after John XXIII’s death, its foundational documents bear the imprint of his vision. Lumen Gentium (1964) redefined the Church as the “People of God,” stressing baptismal equality and the universal call to holiness. Gaudium et Spes (1965) examined the Church’s relationship with the modern world and called Catholics to engage with contemporary social issues as a direct expression of the Gospel. These texts encouraged the faithful to understand their daily responsibilities—family life, work, and political participation—as participation in Christ’s Kingdom. By promoting dialogue with other Christians, non-Christian religions and secular society, the documents helped shift Catholic self-understanding from a defensive posture to one of active service. The emphasis on religious freedom in Dignitatis Humanae further allowed believers to witness to the Kingdom through persuasion rather than coercion.
Assessment and Limitations
John XXIII’s initiatives undoubtedly widened Catholic engagement with social questions and ecumenical dialogue. Yet the implementation of Vatican II revealed tensions between renewal and continuity that he had only partly anticipated. Some interpretations emphasised radical discontinuity, while others stressed fidelity to tradition. Nevertheless, the structural changes he initiated—collegiality among bishops, vernacular liturgy, and a renewed social conscience—provided lasting mechanisms through which Catholics could continue to embody the person of Jesus in public life.
In conclusion, Pope John XXIII encouraged adherents to build the Kingdom of God by reforming the Church’s structures and teaching so that they more closely mirrored Christ’s own ministry. The convocation of the Second Vatican Council, together with his encyclicals and the documents that followed, provided both theological foundations and practical directions for living the Gospel in the modern world. Although challenges of interpretation remain, his legacy continues to shape Catholic efforts to make the Kingdom present through justice, peace and service.
References
- Alberigo, G. and Komonchak, J.A. (eds) (1995–2006) History of Vatican II, 5 vols. Maryknoll: Orbis; Leuven: Peeters.
- O’Malley, J.W. (2008) What Happened at Vatican II. Cambridge, MA: Belknap Press.
- Pope John XXIII (1961) Mater et Magistra. Vatican City: Libreria Editrice Vaticana.
- Pope John XXIII (1963) Pacem in Terris. Vatican City: Libreria Editrice Vaticana.
- Rhodes, A. (1973) The Vatican in the Age of the Dictators, 1922–1945. London: Hodder and Stoughton.
- Tanner, N.P. (ed.) (1990) Decrees of the Ecumenical Councils, 2 vols. London: Sheed & Ward.
