6 Every renewal of the Church is essentially grounded in an increase of fidelity to her own calling. Undoubtedly this is the basis of the movement toward unity. Christ summons the Church to continual reformation as she sojourns here on earth. The Church is always in need of this, in so far as she is an institution of men here on earth. Thus if, in various times and circumstances, there have been deficiencies in moral conduct or in church discipline, or even in the way that church teaching has been formulated - to be carefully distinguished from the deposit of faith itself - these can and should be set right at the opportune moment. Church renewal has therefore notable ecumenical importance. Already in various spheres of the Church's life, this renewal is taking place. The Biblical and liturgical movements, the preaching of the word of God and catechetics, the apostolate of the laity, new forms of religious life and the spirituality of married life, and the Church's social teaching and activity - all these should be considered as pledges and signs of the future progress of ecumenism.
Source: Unitatis Redintegratio (Vatican.va)