November 2nd is All Souls Day, sometimes called the Day of the Dead. On this day, and during the month of November, the Church prays in a special way for the souls of the faithful departed, and individuals pray especially for those whom they have known and loved. The Holy Souls in purgatory died in the mercy of God, thus they are called "holy." However, because they still had attachment to sin at the time of their death, they must undergo the spiritual purification of their souls before they are able to fully love God with their whole heart, mind, and soul for all eternity. As they are nevertheless part of the communion of saints, they depend upon us to help ease their suffering and quickly advance them through their purification so that they can join the saints in heaven. Those in purgatory cannot pray for themselves, this is why they are also called "poor." They can no longer merit anything for themselves and rely entirely on living souls to pray and make sacrifices on their behalf.