Prayer for Holy Souls in Purgatory

It is said that our Lord promised Saint Gertrude that 1000 souls would be released from purgatory each time this prayer is said devoutly.

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.