To understand the Rosary better it is well to recall how St. Dominic conceived it under the inspiration of Our Lady at a time when southern France was ravaged by the Albigensian heresy – a heresy which denied the infinite goodness and omnipotence of God by admiring a principle of evil which was often victorious. Not only did Albigensianism attack Christian morality, but it was opposed to dogma as well – to the great mysteries of creation, the redemptive incarnation, the descent of the Holy Ghost, the eternal life to which we are called.
It was at that moment that Our Blessed Lady made known to St. Dominic a kind of preaching till then unknown, which she said would be one of the most powerful weapons against future errors and in future difficulties. Under her inspiration, St. Dominic went into the villages of the heretics, gathered the people, and preached to them the mysteries of salvation- the Incarnation, the Redemption, Eternal life. As Mary had taught him to do, he distinguished the different kinds of mysteries, and after each short instruction he had ten Hail Marys recited- somewhat as might happen even today at a Holy Hour. And what the word of the preacher was unable to do, the sweet prayer of the Hail Mary did for hearts. As Mary had promised, it proved to be a most fruitful form of preaching.
If we live by prayer of which St. Dominic’s preaching is the example our joys, our sorrows, and our hopes will be purified, elevated and spiritualized. We shall see that Jesus, Our Saviour and Our Model, wishes to make us like Himself, first communicating to us something of His infant and hidden life, then something of His sorrows, and finally making us partakers of His glorious life for all eternity.
From The Mother of the Saviour and Our Interior Life by Fr. Reginald Garrigou-Lagrange, O.P.