All Souls Day commemorates the faithful departed, especially those in purgatory.
The Commemoration of All the Faithful Departed, commonly known as All Souls Day, is observed on November 2nd. On this day, the Church remembers all the souls in purgatory, praying for their purification and entrance into heavenly glory.
Catholic teaching holds that those who die in God's grace but are not yet perfectly purified undergo purification after death to achieve the holiness necessary for heaven:
"If any man’s work is burned, he will suffer loss, but he himself will be saved, but as through fire." — 1 Corinthians 3:15
The Catechism explains: "All who die in God's grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven" (CCC 1030).
From the earliest times, Christians have prayed for the deceased. The practice appears in Scripture:
"But if he was looking forward to an honorable memorial of gratitude laid up for those who die in godliness, then the thought was holy and godly." — 2 Maccabees 12:45
The Church teaches that our prayers, good works, and especially the Holy Sacrifice of the Mass can help the souls in purgatory complete their purification.
All Souls follows directly after All Saints (November 1st). While All Saints celebrates those who have reached heaven, All Souls focuses on those still being purified. Together, these feasts express the Church's belief in the communion of saints—the spiritual bond uniting the Church Triumphant (in heaven), the Church Suffering (in purgatory), and the Church Militant (on earth).
The traditional prayer for the dead captures the Church's hope:
"Eternal rest grant unto them, O Lord, and let perpetual light shine upon them. May they rest in peace. May their souls and the souls of all the faithful departed, through the mercy of God, rest in peace. Amen."