The following invocation was adapted by me from one written by Rev. Judith Lewis. She wrote it for invoking the God at Samhain. I have it in my Book of Shadows and when I reread it I thought it would make a wonderful ancestor invocation after a few changes.
Death walks among us as you pass your way.
Your time has come and gone, the wheel turns.
You have been the spring, the rejoicing summer,
the dying autumn, the still, deep winter.
You are the sorrow, the sadness,
and the coming of death to us all.
Back to the Mother who gave you birth
and nurtured you upon this earth.
Back to the womb of the darkest night,
Back to the chamber of rebirth.
And in that sleep which so restores,
You pass once more, as do we all,
to the Mother to be reborn.
Join us now, before you leave us,
Join us in rejoicing in life.
For without it, there is no death and rebirth.
And so is the cycle and the Lady's way.
Blessed be you, our Ancestors.
Blessings darks and deep!