Catechism of the Catholic Church §1690 — excerpt
A farewell to the deceased is his final "commendation to God" by the Church. It is "the last farewell by which the Christian community greets one of its members before his body is brought to its tomb."
This translation is under copyright, so only the cited words are quoted here. Follow the link for the full text. Translation: English translation of the Catechism of the Catholic Church, 2nd ed. (Libreria Editrice Vaticana), as posted at vatican.va.
Also cites: OCF 10 · St. Simeon of Thessalonica, De ordine sepulturae. 336: PG 155, 684