Catholic Encyclopedia (1913)/Libera Me
(Domine, de morte aeterna, etc.).
The responsory sung at funerals. It is a responsory of redundant form, having two versicles ("Tremens factus sum" and "Dies illa"). As in all the Office for the Dead, the verse "Requiem aeternam" takes the place of "Gloria Patri"; then all the first part, down to the first versicle, is repeated. Its form therefore is exceptional, considerably longer than the normal responsory. It is a prayer in the first person singular for mercy at the Last Day. This should no doubt be understood as a dramatic substitution; the choir speaks for the dead person. A great part of our Office for the Dead is made up of such prayers about the Last Day, the meaning of which appears to refer rather to the people who say them than to the dead (the sequence "Dies irae", most of the Vespers, Matins, and Lauds).
Another dramatic substitution is involved in the prayers of this responsory (and throughout the Office for the Dead) that the person for whom we pray may be saved from hell. That question was settled irrevocably as soon as he died. This is one instance of the dramatic displacement or rearrangement of the objective order of things that occurs continually in all rites (compare for instance in the baptism service the white robe and shining light given after the essential form, in the ordination of priest the power to forgive sins given after the man has been ordained and has concelebrated, the Epiclesis in Eastern liturgies, etc.). The explanation of all these cases is the same. Since we cannot express everything at one instant, we are forced to act and speak as if things really simultaneous followed each other in order. And in the eternity of God all things (including our consecutive prayers) are present at once — nunc stans aeternitas. The responsory "Libera me" is begun by a cantor and continued by the choir in the usual way (the cantor alone singing the versicles) at the beginning of the "Absolution", that is the service of prayers for the dead person said and sung by the bier immediately after the Mass for the Dead. As soon as Mass is over the celebrant exchanges his chasuble for a (black) cope (all the sacred ministers of course take off their maniples) and chants the prayer "Non intres in judicium". Then "Libera me" is sung. Meanwhile the celebrant puts incense into the thurible, assisted by the deacon. During the whole Absolution the subdeacon stands at the head of the bier, facing the altar, with the processional cross.
The ninth responsory of Matins for the Dead also begins with "Libera me", but continues a different text (Domine, de viis inferni, etc.). This is built up according to the usual arrangement (with "Requiem aeternam" instead of "Gloria Patri"). But on All Souls' Day (2 November), and whenever the whole Office of nine lessons is said, the "Libera me" of the Absolution is substituted for it. The Vatican Gradual gives the new chant for the "Libera me" after the Mass for the Dead.