In the Church, November is especially dedicated to suffrages made on behalf of the poor souls in Purgatory. The most efficacious prayer, of course, is that of the Holy Sacrifice of the Mass, followed by the daily Rosary.
Still, there are other sacrifices we can also offer. One prayer, most commonly called "St. Gertrude's Prayer," was dictated by Our Lord to St. Gertrude the Great, a Benedictine cloistered nun and a mystic. In the twelfth century, the Lord told the Saint that this prayer (approved and recommended by M. Cardinal Pahiarca of Lisbon, Portugal on March 4, 1936) releases 1,000 Souls from Purgatory each time it is offered.
"Eternal Father, I offer Thee the Most Precious Blood of Thy Divine Son, Jesus, in union with the Masses said throughout the world today, for all the holy souls in Purgatory, for sinners everywhere, for sinners in the universal church, those in my own home and within my family. Amen."
Isn't it a most wonderful prayer to add to the conclusion of our family Rosaries? It is true that the Rosary itself is such a powerful prayer to the Holy Trinity, that by itself it can empty Purgatory. Yet making use of the St. Gertrude Prayer also helps us further develop a holy compassion for the poor souls, who always await our spiritual assistance. Furthermore, it is such a brief prayer that we can offer it many times throughout the day. At whatever time we pray it, whether during the day or at the beginning or end of our Rosaries, we should never forget: For each person who prays the St. Gertrude Prayer just once, there are 1,000 souls released from the fires of Purgatory into the glories of Heaven. Why not offer it at least five times in succession, in honor of Christ's Holy Wounds, every day? Each member of the family who does so will daily assist five thousand souls.
St. Gertrude's life was the mystic life of the Cloister – a Benedictine nun. She meditated on the Passion of Christ, which many times brought a flood of tears to her eyes. She did many penances and Our Lord appeared to her many times. She had a tender love for the Blessed Virgin and was very devoted to the suffering souls in Purgatory. She died in 1334. Her feast day is November 16th. (From Prayer of St. Gertrude the Great)