2 The Church is most successful in this work of sanctification when it is possible for her, through the mercy of God, to hold up to the imitation of the faithful one or other of her dearest children who has made himself conspicuous by the practice of every virtue. This work of sanctification is of the very genius of the Church, since she was made by Christ, her Founder, not only holy herself but the source of holiness in others. All who accept the guidance of her ministry should, by the command of God, do everything in their power to sanctify their own lives. As St. Paul says, "This is the will of God, your sanctification." (I Thess . iv, 3) Christ Himself has taught what this sanctification consists in - "Be ye therefore perfect as your heavenly Father is perfect." ( Matt. v, 48)
Source: Rerum Omnium Perturbationem (Vatican.va)