FLMILW – CTOMC

 Proverbs  30:18-20 would be at odds with your translation..

From http://www.outreachjudaism.org/alma.htm

To quote:
There are three things which are too wonderful for me, four which I do not understand: the way of an eagle in the sky, the way of a serpent on a rock, the way of a ship in the middle of the sea, and the way of a man with a young woman [b’alma].  This is the way of an adulterous woman: she eats and wipes her mouth, and says, “I have done no wrong.”In the above three verses, King Solomon compares a man with analma to three other things: an eagle in the sky, a serpent on a rock, and a ship in the sea.  What do these three things all have in common?  They leave no trace.  After the eagle has flown across the sky, determining that the eagle had ever flown there is impossible. Once a snake has slithered over a rock, there is no way to discern that the snake had ever crossed there (as opposed to a snake slithering over sand or grass, where it leaves a trail).  After a ship has moved across the sea, the water comes together behind it and there is no way to tell that a ship had ever passed through there.  Similarly, King Solomon informs us that once a man has been with an almathere is also no trace of the fornication that had occurred between them.  Therefore, in the following verse (verse 20) King Solomon explains that once this adulterous woman has eaten (a metaphor for her fornication), she removes the trace of her sexual activity by exclaiming, “I have done no wrong.”  The word alma clearly does not mean virgin.later on …In the same way that in the English language the words “young woman” have no bearing on whether virginity is present or not, in the Hebrew language there is no relationship between the words almaand virgin.  On the contrary, it is usually a young woman who bears children.  Had Isaiah wished to speak about a virgin birth, he would have used the word betulah1 not alma.  Betulah is a common word in the Jewish scriptures, and can only mean “virgin.”

As to your contention that alma is translated as parthenos in Greek …

From http://lists.ibiblio.org/pipermail/b-hebrew/2007-July/032841.html

” ….Professor Schmitt agrees: “From significant passages one sees that the
word’s meaning is not that of the modern English word, one who ahs not
experienced sexual intercourse. The Hebrew word is usually qualified by a
phrase such as ‘who has never known a man’ (e.g. Ge, 24:16, Num 31:18) when
the word is used specifically to mean what the word ‘virgin’ means
today….In later legal terminology, the Bible’s usage approaches the modern
use. One can compare that development to the gradual specialization of the
German word ‘Jungfrau’ from ‘young woman’ to ‘virgin.’”

The meaning of “parthenos” seems to have been similar. When I was curious
about why the LXX used that word to translate almah, and inquired of
acquaintances knowledgeable in Greek, they told me, much to my surprise,
that the word parthenos, despite the common impression to the contrary, did
not always denote a virgin. And it appears that to the authors of the LXX
it did not.

” …Shechem, having raped Dinah (Genesis 34:2), subsequently
told his father Hamor that he wished to marry the girl. The Revised Standard
Version translates his request, ‘Get me this maiden [parthenos] for my wife’
(Genesis 34:4), a perfectly good rendition of the Hebrew text, which uses
the word yaldah for what RSV translates as ‘maiden.’ The point is that this
maiden, the just-raped Dinah, is twice called a parthenos in the Septuagint
(Genesis 34:3, Genesis 34:4).” This suggests pretty clearly that the
writers of the Septuagint did not understand parthenos to mean virgin.”

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