Blessed Albert the Great who had Saint Thomas Aquinas as his disciple learned in a revelation that by simply thinking of or meditating on the passion of Our Lord Jesus Christ, a Christian gains more merit than if he had fasted on bread and water every Friday for a whole year, or had beaten himself with his discipline once a week until the blood flowed, or had recited the whole Book of Psalms every day. If this is so, then how great must be the merit that we can gain by the Holy Rosary which commemorates the whole life and passion of Our Savior!
One day Our Lady revealed to Blessed Alan that, after the Holy Sacrifice of the Mass, which is the most important as well as the living memorial of Our Blessed Lord's passion there could not possibly be a finer devotion or one of greater merit than that of the Holy Rosary, which is like a second memorial and representation of the life and passion of Our Lord Jesus Christ.
Father Dorland says that in 1481 Our Lady appeared to Venerable Dominic, the Carthusian, who lived at Treves, and said to him: "Whenever one of the faithful who is in a state of grace says the Rosary while meditating on the mysteries of the life and passion of Jesus Christ, he obtains full and entire remission of all his sins."
Our Lady also said to Blessed Alan: "I want you to know that, although there are numerous indulgences already attached to the recitation of my Rosary, I shall add many more to every fifty Hail Marys (each group of five decades) for those who say them devoutly, on their knees----being, of course, free from mortal sin. And whosoever shall persevere in the devotion of the Holy Rosary, saying these prayers and meditations, shall be rewarded for it; I shall obtain for him full remission of the penalty and of the guilt of all his sins at the end of his life. Do not be unbelieving, as though this is impossible. It is easy for me to do because I am the Mother of the King of Heaven, and He calls me full of grace. And, being full of grace, I am able to dispense grace freely to my dear children."
Saint Dominic was so convinced of the efficacy of the Holy Rosary and of its great value that, when he heard confessions, he hardly ever gave any other penance. You have seen an example of this already in the story that I told you of the lady in Rome to whom he gave one single Rosary for her penance. Saint Dominic was a great Saint and other confessors should be sure to walk in his footsteps by asking their penitents to say the Rosary together with meditation on the sacred mysteries, rather than giving them other penances which are less meritorious and less pleasing to God, less likely to help them advance in virtue and not as efficacious as the Rosary for helping them avoid falling into sin. Moreover, while saying the Rosary, people gain countless indulgences which are not attached to many other devotions.
And, as Abbe Blosius says: "The Rosary, with meditation on the life and passion of Jesus Christ, is certainly most pleasing to Our Lord and His Blessed Mother and is a very successful means of obtaining all graces; we can say it for ourselves as well as for others for whom we wish to pray and for the whole Church. Let us turn, then, to the Holy Rosary in all our needs, and we shall infallibly obtain the graces we ask of God to save our souls."