1) Mary gave 15 promises to those who prayed the rosary
Alanus de Rupe, a 15th century Dominican preacher, was visited by the Blessed Virgin Mary, who gave 15 promises to Christians who prayed the rosary . These include the assurance of receiving the sacraments at the time of death; never being conquered by misfortune; and her own special protection.

2) To obtain world peace
“Continue praying the rosary every day in honor of Our Lady of the Rosary, in order to obtain peace for the world and the end of the war, because only she can help you.” This is what Our Lady of Fatima said to Lucia dos Santos and her cousins, Francisco and Jacinta Marto, in June 1917.

The Blessed Mother visited the children in Fatima, Portugal, from May 13, 1917, to October 13, 1917, a period that culminated in the Miracle of the Sun, otherwise known as “The Day the Sun Danced.”

3) Time to reflect on the Gospel mysteries
The rosary consists of decades made of certain prayers: The Our Father, the Hail Mary and the Glory Be. During each decade, we are invited to reflect on the Joyful, Sorrowful, Glorious and Luminous mysteries revealed in the Gospels.

In these mysteries, we rediscover, examine and ponder the stories from the Gospels, and discover the real meaning of those events in the silence of our hearts.

4) Spiritual healing
Speaking of silence, another purpose of praying the rosary is to allow God to enter our hearts. As we meditate through the repetitive prayers, we can better hear God. We hear him in the silence of our hearts, where Christ’s spirit dwells.

In that silence, we become more connected with the Father, the Son, and the Holy Spirit.

Jesus reveals to us that “You shall love the Lord your God with all your heart, and with all your soul, and with all your strength, and with all your mind.” But to do this, we must make time for him. The rosary is the perfect way to make time for God and for spiritual healing. Take 15 minutes a day, the time it takes to pray the rosary, to open your heart to him.

5) Prayer works
The power of prayer is unspeakable. It is our lifeline to God.

In 1571, Pope Pius V organized a group of Christian forces, known as the Holy League, in defense of an imminent invasion by the Ottoman Empire. Before a battle with the Ottoman fleet in the Gulf of Patras, in the Ionian Sea, the pope called on all of Europe to pray the rosary for victory. These prayers were answered, with the Holy League defeating the much larger Ottoman forces on Oct. 7 at the battle of Lepanto.

To commemorate the victory, Pius V established the feast day of “Our Lady of Lepanto” –– also known as Our Lady of Victory or Our Lady of the Rosary.” (Five Reasons You Should Pray the Rosary | KofC.org)