Please note that this belief not only has its origins in our Old Testament roots but also in the early history of the church. Inscriptions uncovered on tombs in the Roman catacombs of the second century evidence this practice. For example, the epitaph on the tomb of Abercius, bishop of Hieropolis in Phrygia (d. 180), begs for prayers for the repose of his soul. Tertullian in 211 attested to observing the anniversary of death of the faithful departed with prayers. Moreover, the Canons of Hippolytus (c. 235), one of the earliest missals, explicitly mentions the offering of prayers for the dead during the Mass. The testimony of many of the church fathers also beautifully supports this belief: For example, St. Cyril of Jerusalem (d. 386), in one of his many catechetical discourses, explained how at Mass both the living and dead are remembered, and how the Eucharistic Sacrifice of Our Lord is of benefit to sinners, living and dead; and St. Ambrose (d. 397) preached, “We have loved them during life; let us not abandon them in death, until we have conducted them by our prayers into the house of the Lord.”
When we face the death of someone, even a person who is not Catholic, to have a Mass offered for the repose of his soul and to offer our prayers are more beneficial and comforting than any other sympathy card or bouquet of flowers. Most importantly, we always should remember our own dearly departed loved ones in the holy Mass and through our own prayers and sacrifices to help in their gaining eternal rest.