The power of the Rosary is utterly disproportionate to its simplicity. There is no grace that cannot be obtained, no Goliath that cannot be defeated, through the humble supplication of the Rosary.
We do not hesitate to affirm again publicly that We put great confidence in the Holy Rosary for the healing of evils which afflict our times. Not with force, not with arms, not with human power, but with Divine help obtained through the means of this prayer, strong like David with his sling, the Church undaunted shall be able to confront the infernal enemy, repeating to him the words of the young shepherd: “Thou comest to me with a sword, and a spear, and with a shield; but I come to thee in the name of the Lord of Hosts, the God of armies . . . and all this assembly shall know that the Lord saveth not with sword and spear, for this is his battle, and he will deliver you into our hands” (I Kings 17, 45-47).
Pope Pius XII
15 September, 1951