A prayer is a vital necessity for the Christian life. But through prayer we also can ease the sufferings of the souls in Purgatory by praying for them.
"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"
Say this prayer for the souls in Purgatory. Our Lord told St. Gertrude the Great that 1,000 souls would be released from Purgatory every time this is said! This prayer has now even been "extended to living sinners which would alleviate the indebtedness accrued to them during their lives." Note: This is private revelation. This means that you don't have to believe this to be Catholic although the Church has found this worthy of belief.