Q: May the readings for a Funeral Mass be drawn from other scriptures than those listed in the Order of Christian Funerals?
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A: I treated this question briefly in my book Light in the Darkness. The Order of Christian Funerals allows conferences of bishops to expand the options when several exist, and the Introduction to the Lectionary for Mass says that the selections it offers for Masses for the Dead “can be of assistance in adapting such celebrations to the situation, circumstances, and concerns of the particular groups taking part” (86). It does not explicitly limit the choices to those in the lectionary.
So my personal opinion is yes, the readings for a funeral mass may be drawn from other scriptures. But you’ll find people who disagree with me.