2 The form of prayer We refer to has obtained the special name of "Rosary," as though it represented by its arrangement the sweetness of roses and the charm of a garland. This is most fitting for a method of venerating the Virgin, who is rightly styled the Mystical Rose of Paradise, and who, as Queen of the universe, shines therein with a crown of stars. So that by its very name it appears to foreshadow and be an augury of the joys and garlands of Heaven offered by her to those who are devoted to her. This appears Clearly if we consider the nature of the Rosary of Our Lady. There is no duty which Christ and His Apostles more emphatically urged by both precept and example than that of prayer and supplication to Almighty God. The Fathers and Doctors in subsequent times have taught that this is a matter of such grave necessity, that if men neglect it they hope in vain for eternal salvation. Every one who prays finds the door open to impetration, both from the very nature of prayer and from the promises of Christ. And we all know that prayer derives its chief efficacy from two principal circumstances: perseverance, and the union of many for one end. The former is signified in those invitations of Christ so full of goodness: ask, seek, knock (Matt. vii., 7), just as a kind father desires to indulge the wishes of his children, but who also requires to be continually asked by them and as it were wearied by their prayers, in order to attach their hearts more closely to himself. The second condition Our Lord has born witness to more than once: If two of you shall consent upon earth concerning anything whatsoever they shall ask, it shall be done to them by My Father who is in heaven . For where there are two or three gathered in My name, there am I in the midst of them (Matt. xviii. 19, 20). Hence that pregnant saying of Tertullian: Let us gather into an assembly and congregation that we may, as it were, make up a band and solicit God ( Apologet . c. xxxix): such violence is pleasing to God ; and the memorable words of Aquinas: It is impossible that the prayers of many should not be heard, if one prayer is made up as it were out of many supplications . (In Evang. Matt. c. xvii). Both of these qualities are conspicuous in the Rosary. For, to be brief, by repeating the same prayers we strenuously implore from Our Heavenly Father the Kingdom of His grace and glory; we again and again beseech the Virgin Mother to aid us sinners by her prayers, both during our whole life and especially at that last moment which is the stepping-stone to eternity. The formula of the Rosary, too, is excellently adapted to prayer in common, so that it has been styled, not without reason, "The Psalter of Mary." And that old custom of our forefathers ought to be preserved or else restored, according to which Christian families, whether in town or country, were religiously wont at close of day, when their labours were at an end, to assemble before a figure of Our Lady and alternatelyrecite the Rosary. She, delighted at this faithful and unanimous homage, wasever near them like a loving mother surrounded by her children, distributing tothem the blessings of domestic peace, the foretaste of the peace of heaven.Considering the efficacy of public prayer, We, among other decrees which we havefrom time to time issued concerning the Rosary, have spoken thus: "It isOur desire that in the principal church of each diocese it should be recitedevery day, and in parish churches on every feast-day (Apostolic Letter Salutaris Ille , 24th December, 1883). Let this be constantly and devoutly carried out. Wealso see with joy the custom extended on other solemn occasions of publicdevotion and in pilgrimages to venerated shrines, the growing frequency of whichis to be commended. This association of prayer and praise to Mary is bothdelightful and salutary for souls. We ourselves have most strongly experiencedthis - and Our heart rejoices to recall it - when at certain times in OurPontificate We have been present in the Vatican basilica, surrounded by greatcrowds of all classes, who united with Us in mind, voice, and hope, earnestlyinvoked by the mysteries and prayers of the Rosary, her who is the most powerfulpatroness of the Catholic name .
Source: Fidentem Piumque Animum (Vatican.va)