The Creed or the Symbol of the Apostles, which is said on the crucifix of the rosary, is a holy summary of all the Christian truths. It is a prayer that has great merit, because faith is the root, foundation and beginning of all Christian virtues, of all eternal virtues, and of all prayers that are pleasing to God. "Anyone who comes to God must believe," and the greater his faith the more merit his prayer will have, the more powerful it will be, and the more it will glorify God.
I shall not take time here to explain the Creed word for word, but I cannot resist saying that the first words, "I believe in God," are wonderfully effective as a means of sanctifying our souls and putting the devils to rout, because these words contain the acts of the three theological virtues of faith, hope and charity.
It was by saying these words that many saints overcame temptations, especially those against faith, hope or charity, either during their lifetime or at the hour of their death. They were also the last words of Saint Peter, Martyr. A heretic had cleft his head in two by a blow of his sword, and although Saint Peter was at his last gasp, he managed to trace these words in the sand with his finger.
The holy Rosary contains many mysteries of Jesus and Mary, and since faith is the only key which opens up these mysteries for us, we must begin the Rosary by saying the Creed very devoutly, and the stronger our faith the more merit our Rosary will have.
This faith must be lively and informed by charity; in other words, to recite the Rosary properly it is necessary to be in God's grace, or at least seeking it. This faith must be strong and constant, that is, one must not be looking for sensible devotion and spiritual consolation in the recitation of the Rosary; nor should one give it up because the mind is flooded with countless involuntary distractions, or because one experiences a strange distaste in the soul or an almost continual and oppressive fatigue of the body. Neither feelings, nor consolation, nor sighs, nor transports, nor the continual attention of the imagination are needed; faith and good intentions are quite enough. Sola fides sufficit.
- from The Secret of the Rosary, bySaint Louis-Marie Grignion de Montfort