On this day, we commemorate with all of the faithful departed, who because of one sin or another, cannot yet behold the face of God. They're deprived of this heavenly bliss and privilege, not because they're damned, but because, they need to undergo a period of purgation in order to become Worthy to see God's eternal blessedness.
It is therefore our obligation, to pray for them earnestly, so that they might obtain God's mercy and consequently, behold his face.
We pray for them, because they're incapable of praying for themselves. This too is a spiritual work of mercy that ensures that when we too are unfortunate enough to be in their state, both they who we've prayed for, and the living might also remember us in turn.
May the souls of all the faithful departed, through the mercy of God, rest in peace. Amen .