Catholic Encyclopedia (1913)/De Profundis
("Out of the depths"). First words of Psalm 129. The author of this Psalm is unknown; it was composed probably during the Babylonian Exile, or perhaps for the day of penance prescribed by Esdras (I Esd., ix, 5-10). The hard school of suffering during the Exile had brought the people to the confession of their guilt an had kindled in their hearts faith and hope of the Redeemer and confidence in the mercy of God. The De profundis is one of the fifteen Gradual Psalms, which were sung by the Jewish pilgrims of their way to Jerusalem, and which are still contained in the Roman breviary. It is also one of the seven Penitential Psalms which, in the East and the West, were already used as such by the early Christians. In the Divine Office the De profundis is sung every Wednesday at Vespers, also at the second Vespers of Christmas, the words Apud Dominum misericordia et copiosa apud eum redemptio, reminding us of the mercy of the Father Who sent His Son for the redemption of mankind. It is also used in the ferial prayers of Lauds and in the Office of the Dead at Vespers. The Church recites this psalms principally in her prayers for the dead; it is the psalm of the holy souls in purgatory, the words of the Psalmist applying well to the longing and sighing of the souls exiled from heaven. It is recited at funerals by the priest, before the corpse is taken out of the house to the church.