This way of praying is of the greatest benefit to our souls because:
1. Normally our minds are far more alert during public prayer than they are when we pray alone.
2. When we pray in common, the prayer of each one belongs to us all and these make but one great prayer together, so that if one person is not praying well, someone else in the same gathering who prays better may make up for his deficiency. In this way those who are strong uphold the weak, those who are fervent inspire the lukewarm, the rich enrich the poor, the bad are counted as good. How can a measure of cockle be sold? This can be done very easily by mixing it up with four or five barrels of good wheat.
3. Somebody who says his Rosary alone only gains the merit of one Rosary, but if he says it together with thirty other people he gains the merit of thirty Rosaries. This is the law of public prayer. How profitable, how advantageous this is!
4. Urban VIII, who was very pleased to see how devotion to the Holy Rosary had spread in Rome and how it was being said in two groups or choirs, particularly at the convent of Santa Maria Sopra Minerva, attached one hundred days' extra indulgence, toties quoties, whenever the Rosary was said in two choirs. This was set out in his brief "Ad perpetuam rei memoriam," written in the year 1626. So every time you say the Rosary in two groups you gain one hundred days' extra indulgence.
5. Public prayer is far more powerful than private prayer to appease the anger of God and call down His Mercy and Holy Mother Church, guided by the Holy Ghost, has always advocated public prayer in times of public tragedy and suffering.
In his bull on the Rosary, Pope Gregory XIII says very clearly that we must believe (on pious faith) that the public prayers and processions of members of the Confraternity of the Holy Rosary were largely responsible for the great victory over the Turkish navy at Lepanto which Almighty God granted to Christians on the first Sunday of October, 1571.
When King Louis the Just, of blessed memory, was besieging La Rochelle, where the revolutionary heretics had their stronghold, he wrote to his mother to beg her to have public prayers offered for a victorious outcome. The Queen-Mother decided to have the Rosary recited publicly in Paris in the Dominican Church of Faubourg Saint Honore and this was done by the Archbishop of Paris. It was begun on May 20th, 1628.
Both the Queen-Mother and the reigning Queen attended the recitation of the Rosary together with the Duke of Orleans, Cardinal de La Rochefoucault and Cardinal de Berulle, as well as other prelates. The court turned out in full force as well as a large proportion of the general populace. The Archbishop used to read the meditations on the mysteries aloud and then begin the Our Fathers and Hail Marys of each decade while the congregation made up of religious and lay folk answered him. At the end of the Rosary a statue of the Blessed Mother was solemnly carried in procession while the Litany of Our Lady was sung.
This devotion was kept up with admirable fervor every Saturday and resulted in a manifest blessing from Heaven: for on All Saints' Day of the same year the king defeated the English at the island of Re and made his triumphant entry into La Rochelle. This goes to show the great power of public prayer.
Finally, when people say the Rosary together it is far more formidable to the devil than one said privately, because in this public prayer it is an army that is attacking him. He can often overcome the prayer of an individual, but if this prayer is joined to that of other Christians, the devil has much more trouble in getting the best of it. It is very easy to break a single stick, but if you join it to others to make a bundle it cannot be broken. "In union there is strength." Soldiers join together in an army to overcome their enemies; wicked people often get together for parties of debauchery and dancing, and evil spirits join forces in order to make us lose our souls. So why, then, should not Christians join forces to have Jesus Christ present with them when they pray, to appease Almighty God's anger, to draw down His grace and mercy upon us, and to frustrate and overcome the devil and his Angels more forcefully?
Dear Rosary Confraternity members, whether you live in town or in the country, near your parish Church or near a chapel, go there at least every evening (with the parish priest's approval, of course), together with all those who want to recite the Rosary in two choirs. If a Church or a chapel is not available say the Rosary together in your own or a neighbor's house. This is a holy practice which Almighty God, in His mercy, has set up in places where I have preached missions----to safeguard and increase the good brought about by these missions and to prevent further sin.
Before the Holy Rosary took root in these small towns and villages, dances and parties of debauchery went on all the time; dissoluteness, wantonness, blasphemy, quarrels and feuds flourished. One heard nothing but evil songs and double-meaning talk. But now nothing is heard but hymns and the chant of the Our Father and Hail Mary. The only gatherings to be seen are those of twenty, thirty or a hundred or more people who, at a fixed hour, sing Almighty God's praises just as religious do. There are even places where the Rosary is recited in common----five mysteries at a time----at three special times every day. What a blessing from Heaven this is!
Just as there are wicked people everywhere, do not expect to find that the place you live in is free of them; there will be some who will be certain to avoid coming to Church for the Rosary and they may even make fun of it and will probably do everything in their power to stop you from going, exerting their influence by bad example and bad language. But do not give up. As these wretched souls will have to be separated from God and Heaven for all eternity because their place will be in Hell, already here on earth they have to be separated from the company of Christ Our Lord and His servants and hand-maids.
From page 96,97, 98 and 99
Nihil Obstat, Gulielmus F. Hughes, S.T.L., Censor Librorium
Imprimatur, Thomas Edmundus Molloy, S.T.D., Archiepiscopus-Episcopus Brooklyniensis, 1954 For more, see The Holy Rosary
St. Louis-Marie Grignon de Montfort's The Secret of the Rosary