And Adam knew that his wife Eve had conceived
from Sammael the angel (of death)
and she became pregnant and bore Cain.
And he was like those on high and not like those below.
And she said: "I have got a man from the angel of the LORD."
My problem with this translation is that the words in italics above are not found in any text of Pseudo-Jonathan. The only surviving manuscript of Pseudo-Jonathan (PsJ), in the British Museum, reads, according to the publication of it by Clarke, "And Adam knew that Eve his wife was pregnant from Sammael, angel of the Lord." The standard printed text (editio princeps) as published in the rabbinic bible reads: "And Adam knew Eve his wife, that she had desired the angel; and she conceived and bore Cain, and she said, I have acquired a man, the angel of the Lord."
Obviously the version with the addition is closer to the editio princeps than to the London MS, but neither text (and they are the only witnesses to the text of PsJ) has the addition. Nevertheless, the belief that the words really are in PsJ is widespread. James Kugel quotes the latter part of PsJ's version as "He resembled the upper ones [angels] and not the lower ones, and she [therefore] said, I have acquired a man, indeed, an angel of the Lord" (The Bible as it Was, p. 86). Birger Pearson, in an essay in The Rediscovery of Gnosticism (1981) quotes the same version (p. 479). And Phillip Davies, in the Blackwell Reader in Judaism (2001), does the same (p. 40). These are all reputable scholars.
As far as I can tell, there is no evidence that any version of PsJ (or any other targum) contains these words. However, another text that has some affinities to PsJ, the Hebrew Pirke de-Rabbi Eliezer, in relating the story of Cain's conception, says "she saw his likeness that it was not of the earthly beings, but of the heavenly beings." Is that where these words come from? Or is there a version of the text of PsJ that I'm not aware of?
I'm frankly stumped as to the source of this spurious text of the targum. Do any of my readers have any insight?
UPDATE (3/2): Many thanks to those who have left comments below. Andy, can you point me towards a source for that quote?