Prayer for All Souls Day 

The Prayer of St. Gertrude, below, is one of the most famous of the prayers for souls in purgatory. St. Gertrude the Great (pictured at left) was a Benedictine nun and mystic who lived in the 13th century. According to tradition, our Lord promised her that 1000 souls would be released from purgatory each time it 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. Amen."
 

What is All Souls Day?  All Souls Day is when the Church commemorates and prays for the holy souls in Purgatory, undergoing purification of their sins before entering heaven. All Souls Day is November 2nd, right after All Saints Day. These All Souls Day Prayers relate to these themes, including praying for those in Purgatory. More Info: All Souls Day. [sources : http://www.churchyear.net/allsoulsprayers.html & others]