8 This statement of the Decree Unitatis Redintegratio is to be read in the context of the complete teaching of the Second Vatican Council. The Council expresses the Church's decision to take up the ecumenical task of working for Christian unity and to propose it with conviction and vigour: "This sacred Synod exhorts all the Catholic faithful to recognize the signs of the times and to participate actively in the work of ecumenism". In indicating the Catholic principles of ecumenism, the Decree Unitatis Redintegratio recalls above all the teaching on the Church set forth in the Dogmatic Constitution Lumen Gentium in its chapter on the People of God. At the same time, it takes into account everything affirmed in the Council's Declaration on Religious Freedom Dignitatis Humanae . The Catholic Church embraces with hope the commitment to ecumenism as a duty of the Christian conscience enlightened by faith and guided by love. Here too we can apply the words of Saint Paul to the first Christians of Rome: "God's love has been poured into our hearts through the Holy Spirit"; thus our "hope does not disappoint us" ( Rom 5:5). This is the hope of Christian unity, which has its divine source in the Trinitarian unity of the Father, the Son and the Holy Spirit.
Source: Ut Unum Sint (Vatican.va)