I happened to see this claim in an online puff for the curious theories of Acharya S:
The salvific death and resurrection at Easter of the god, the initiation as remover of sin, and the notion of becoming “born again,” are all ages-old Pagan motifs or mysteries rehashed in the later Christianity. The all-important death-and-resurrection motif is exemplified in the “Parisian magical papyrus,” a Pagan text ostensibly unaffected by Christianity:
“Lord, being born again I perish in that I am being exalted, and having been exalted I die; from a life-giving birth being born into death I was thus freed and go the way which Thou has founded, as Thou hast ordained and hast made the mystery.”
This followed remarks about Easter being celebrated in pagan Mexico (!).
It is a golden rule, when dealing with supposed quotations in twaddle, always to verify those quotations. A look in Google books shows that these two paragraphs are quoted verbatim from Acharya S, Suns of god, 2004, p.503. A reference ’18’ is given, but unfortunately the preview does not include the references.
A quick search in Betz, The Greek Magical papyri in translation, reveals no matches for “born again”. Hmm.
Searching for the words reveals a possible source: the “Pagan Background of Early Christianity”, p.244 by W. R. Halliday (London, 1925: not a headbanger source) might be the source. I’ve not been able to find this book online, tho. But in a Google books preview it seems to refer to Dieterich’s publication of the so-called “Mithras liturgy”, so the words should be at the end of this. But I can find nothing relevant in Meyer’s translation here.
UPDATE: It is indeed in Meyer:
O Lord, while being born again, I am passing away; while growing and having grown, I am dying; while being born from a life-generating birth, I am passing on, released to death– as you have founded, as you have decreed, and have established the mystery…