All Souls: "The souls of the just are in the hand of God."

As gold in the furnace, he proved them, and as sacrificial offerings he took them to himself.

-- Wis 3:1-9

"We believe that the souls of all who die in Christ's grace . . . are the People of God beyond death. On the day of resurrection, death will be definitively conquered, when these souls will be reunited with their bodies" (Paul VI, CPG § 28).

-- CCC 1052

The Eucharistic sacrifice is also offered for the faithful departed who "have died in Christ but are not yet wholly purified," so that they may be able to enter into the light and peace of Christ:

Put this body anywhere! Don't trouble yourselves about it! I simply ask you to remember me at the Lord's altar wherever you are. (Saint Monica)

Then, we pray [in the anaphora] for the holy fathers and bishops who have fallen asleep, and in general for all who have fallen asleep before us, in the belief that it is a great benefit to the souls on whose behalf the supplication is offered, while the holy and tremendous Victim is present. . . . By offering to God our supplications for those who have fallen asleep, if they have sinned, we . . . offer Christ sacrificed for the sins of all, and so render favorable, for them and for us, the God who loves man.

-- CCC 1371

Art: Purgatory, Les Très Riches Heures du Duc de Berry.