From St Andrews Abbey Website.
St. Benedict blessed by God both in grace and in name, Patriarch of Western Monasticism, and founder of the Order which bears his name, was born in Nursia, Italy, in 480 and died in 547. As the Cross of our Lord Jesus Christ was a chief object of devotion to the early Christians, so it was to Benedict. It was this devotion to the Cross, the sign of our redemption, that gave rise to the medal of St. Benedict, for devotion to the Medal of St. Benedict is above all else devotion to the sign of our salvation. The Saint often employed the sign of the Cross to work miracles and to overcome the devil and his temptations. From the earliest centuries after his death Benedict is represented bearing the Cross of Christ together with the Holy Rule.
The Jubilee Medal of St. Benedict represents on the one side the holy Patriarch holding in the one hand the cross, and in the other the Holy Rule. On the other side is shown a cross with certain letters on and around it. They are in reality ejaculatory prayers which may have been frequently in the mouth of St. Benedict himself. The letters in the angles of the cross, C. S. P. B., stand for the words: Crux Sancti Patris Benedicti. (The Cross of Holy Father Benedict.) On the perpendicular bar of the cross are the letters: C. S. S. M. L., They signify: Crux Sacra Sit Mihi Lux. ( May the Holy Cross be my light.) On the horizontal bar we find: N. D. S. M. D., that is, Non Draco Sit Mihi Dux. ( Let not the Dragon be my guide.) Around the margin may be seen: V. R. S. N. S. M. V. S. M. Q. L. I. V. B. These initials stand for the verses: Vade Retro Satana! Nunquam Suade Mihi Vana. Sunt Mala Quae Libas; Ipse Venena Bibas. ( Be gone, Satan! Suggest not to me thy vain things. The cup thou proffer est me is evil; drink thou thy poison.) These or similar words may have been used by St. Benedict when making use of the sign of the cross against the devil and his temptations.
Above the Cross we find the word PAX ( Peace), the motto of the Benedictine Order, to denote a blessing which the Medal brings upon the devout wearer. On the right side of St. Benedict is the poisoned cup, shattered by the sign of the Cross, which the Saint made over it; on his left we have a raven about to carry away a poisoned loaf of bread sent to the holy Patriarch. Above the cup and the rave stands the inscription: Crux S. Patris Benedicti. ( The Cross of Holy Father Benedict.) Around the edge of the same side are the words: Ejus in Obitu nostro Praesentia Muniamur. ( At our death may we be protected by his presence. Below we read: Ex S. Monte Casino. MDCCCLXXX. Abbey of Monte Cassino, 1880.)
No special way of carrying or applying the Medal is prescribed. It may be worn about the neck, attached to the scapular or the Rosary, or otherwise carried about one's person. It may be dipped into the water or medicine to be given to the sick: or it may be applied to their wounds. Often it is placed in the foundations of houses, hung over the doors or on the walls of dwelling places, stables, barns, or attached to automobiles, to call down God's blessing and the protection of St. Benedict, and the power of the Church's blessing. Also no particular prayers are prescribed, as the devout wearing itself is a continual silent prayer. If, however, some extraordinary favor through the use of the Medal is sought, one may make a novena or triduum, making each day the Way of the Cross, or reciting five Our Fathers and Hail Marys in honor of the five wounds of our Lord, and saying some prayers in honor of St. Benedict. In time of temptation, it is advisable to hold the Medal in one's hand, kiss it reverently, and make use of the ejaculatory prayers on the Medal.
The only medal in existence the blessing of which the church has honored with a special exorcism and in the Roman Ritual, is the Medal of Saint Benedict. As in the case in all her greater blessings, the Church begins by exorcising the medals to be blessed, in order to withdraw them from the influence of the evil spirit. Next follows the blessing proper. The following is a translation of a shorter form for blessing the Medal of St Benedict. This blessing must be done by a Benedictine to obtain the full benefits of the medal.
V. Our help is in the name of the Lord.
R. Who made heaven and earth.
I exorcise you, O medals, by God the Father + Almighty, who made heaven and earth and all things that are in them. May all the power of the enemy, the entire diabolical host, all the assaults, all the illusions of Satan be removed and expelled from these medals: that they may be conducive to the health, both of mind and of body, of those who shall use them: In the name of the Father + Almighty, and of Jesus + Christ, His Son, our Lord, and of the Holy + Spirit, the Paraclete, and in the charity of the same Jesus Christ, our Lord, who shall come to judge the living and the dead, and the world by fire. Amen.
Let us pray!
Almighty God, giver of all good things, we humbly beseech you that, through the intercession of Saint Benedict, you will impart to these medals your + benediction: in order that all who carry them and earnestly strive to perform good works, may deserve to obtain health of mind and body, the grace of sanctification, and the indulgences granted to us; also that they may endeavor, with Your merciful help, to escape all the snares and deceits of the devil, and my be able to appear holy and stainless in Your sight. We ask this through Christ, our Lord. Amen.