Prayer for Those we are Bound to Pray for

 Grant, we beseech Thee, O Lord our God, that the souls of Thy servants and handmaidens, the commemoration of whom we keep with special reverence, and for whom we are bidden and are bound to pray, and the souls of all our benefactors, relations, and connections, and all the faithful, may rest in the bosom of Thy Saints; and hereafter, in the Resurrection from the dead, may please Thee in the land of the living. Amen

Efficacy of the Rosary for the Suffering Souls
(from the Manual of the Purgatorial Society 1907)

St. Dominic declared that the redemption of the holy souls from Purgatory is one of the principal effects of the Rosary. The venerable Alanus writes that many of the brethren had assured him that numerous souls had appeared to them whilst reciting the Rosary, and had declared that next to the Holy Sacrifice of the Mass there was no more powerful means of helping the suffering souls than the Rosary. And numerous souls were daily released thereby, who otherwise would have been obliged to remain there for years. St. Alphonsus Liguori, therefore, says: " If we wish to be of assistance to the souls in Purgatory, we must always remember them in our prayers to the Blessed Virgin Mary, and especially offer the holy Rosary for them."

Let us then frequently and with devotion recite the Rosary, which is so pleasing to our Blessed Mother, recommended most especially by Holy Church, discloses to us a rich source of grace, and is so efficacious in relieving the suffering souls and opening Heaven to them. Should our labor prevent us from reciting the entire Rosary every day, let us, at least, say a part of it. This simple homage to the Queen of Heaven will draw great blessing down upon us. And the holy souls will be wonderfully consoled and relieved if this devotion be offered in their behalf.

Prayer:

Graciously hear, O Lord, the prayer we offer Thee in the holy Rosary in honor of Mary, Thy Virgin Mother, for the relief of the souls in Purgatory, while in devout meditation upon Thy holy life and suffering we implore Thy Divine assistance. Thou, who livest and reignest, world without end. Amen.

Special Intercession: Pray for the souls who were most devoted to the holy Rosary. Lord grant them eternal rest, and let perpetual light shine upon them. May they rest in peace. Amen. (Three times.)

Practice: Recite the Rosary for the suffering souls.
Invocation: My Jesus, mercy!