Tradition
St. Gregory the Great
Dialogues
The Fourth Book › Chapter Fifty: Whether the Souls Receive Any Benefit, If Their Bodies Be Buried in the Church.
Chapter Fifty: Whether the souls receive any benefit, if their bodies be buried in the church.
GREGORY. Such as die not in mortal sin receive this benefit by having their bodies buried in the church: for when their friends come thither, and behold their sepulchres, then do they remember them, and pray unto God for their souls: but those that depart this life in the state of deadly sin, receive not any absolution from their sins, but rather be more punished in hell, for having their bodies buried in the church: which thing shall be more plain, if I do briefly tell you what concerning this point hath chanced in our time.
Source: Dialogues (Tertullian.org)