57 It is scarcely necessary to add, Venerable Brothers, how much We depend on the regular clergy to aid in the successful execution of the different parts of Our program. You know as well as We what a magnificent contribution they have made to the interior life of the Church and to the spread of the Kingdom of Christ. They are actuated not only by the precepts but by the counsels of Christ. Both in the holy silence of the cloister and in pious works outside convent walls they exhibit the high ideals of Christian perfection by their works of true piety, by their keeping uppermost in the minds of Christian people the pure ideals of Christ, by the example which they give due to their self-sacrificing renunciation of all worldly comforts and material goods, by their acquisition of spiritual treasures. Because of the consecration of their whole being to the common good, they undertake truly miraculous activities which succor every ill spiritual and bodily, and help all in finding a sure remedy or assistance from the evils which we must encounter. As the history of the Church bears witness, members of the religious orders under the inspiration of God's love, have often gone to such lengths in their work of preaching the Gospel that they have given up their lives for the salvation of souls, thus by their death spreading the unity of the faith and the doctrine of Christian brotherhood and at the same time extending farther and farther the boundaries of the Kingdom of Christ.
Source: Ubi Arcano Dei Consilio (Vatican.va)